My PT is annoyed I haven't given notice...

So patronizing. "I'll warn you though"
I've also had salaried jobs.

I was trying to think of reasons why the PT might have been irritated by the OP cancelling at short notice.
I was also pointing out in my original post that the OP's assumption that the PT wanted to sell the time slot twice might have been wrong.
You've decided to have a go at me, talking about my "Arctic car" in quite a nasty way. There is no need for that.

I'm not engaging with you any further.

No thanks. I don’t want to be self employed, for the very reasons I’ve described. No one is forcing you to do it either. You could get a salaried job.

I’ll warn you though - that’s not always a picnic either. Sometimes I’ll have a quiet week and still get my full salary; other times I’m run ragged and don’t get a penny extra. It’s called reality.

You’re forgetting one fairly key point here. The PT doesn’t want to lose the OP’s business. He can’t be THAT bothered about the cancellations - otherwise the news that the OP wasn’t going to continue would be a positive. If, as you’re trying to portray, he was largely motivated by an altruistic desire to bring fitness to the masses, he’d be delighted that he could take on a new client who appreciated his passion, and whose children would never have the temerity to be ill. And all without having to have a difficult conversation with the OP in which he tells her she’s unreliable so he doesn’t want to work with her anymore.

Yet he’s not treating this as a win. He’s actually pretty pissed off about it. Which makes me think the queue of motivated, appreciative clients who are happy to keep booking him forever isn’t as long as you and some posters are trying to make out.

Get back to me when you've done a couple years of self-employment under similar conditions.

Well at the risk of sounding trite, sometimes life isn’t nice. Particularly at work. So you sat in your car for a bit (quite how cold cars get I don’t know). It’s hardly like being sent down the salt mines. It wasn’t particularly nice for the OP to lose out on both her training session and the money she paid for it - and to have to deal with a sick child on top of that. The PT definitely got the better deal.

Put it this way: let’s say you have a minimum 48 hours notice period for cancellations. If one of your clients cancels 36 hours before a session - plenty of time for you to arrange things so you’re not sitting in this Arctic car of yours - do you think “Awwh, I shouldn’t charge them - it’s not very nice to lose money”? Or do you charge them, as per the terms of your policy - terms to which they agreed - and get a paid hour to yourself?

If you’re happy to take the smooth, you can’t complain about the rough.

She's already paid for the session, so it's her loss, not the PTs.

what do you suggest she does? Send her sick kids to school so she can meet with her PT?

No, they don’t have any sort of a contract that extends past the blocking sessions that have been booked and paid for.

MN is fucking bonkers sometimes. Are there just lots of self employed people on here who feel entitled to the benefits of a permanent contract as well as self employment?

I had a PT like this. He'd cancel on me last minute on occasion. No problem.

But when he found out I was no longer requiring his services, he became a dick. Not a good way to run a business or encourage repeat customers.

As the OP said she'd already made it clear.

You ignored my first point as to how the OP is supposed to know in advance that her children would be ill.

Also how much notice would you give your hairdresser? Three haircut's time? She did tell him. She didn't just disappear. She just didn't re-book. He didn't like it and behaved unprofessionally.

Yes that's when my session is too! It seems to be popular.

You clearly do have a contract, inasmuch as he agrees to provide a service and you agree to pay him. It's just not a written contract.

I’m finding a lot of these posts really infuriating on the OP’s behalf!
Are people being purposefully dense! She clearly stated that she pays in blocks and any sessions she can’t make are already paid for.

I don’t use a PT, but I have 2 activities I do with my toddlers that are also paid in blocks. Those people are self employed and towards the end of each block I get an email with details of the next block that I can either book and pay for, or let them know I’m not returning. I wouldn’t expect to be reprimanded for ruining these people’s livelihoods or reputations for choosing not to book onto the next block!
If this PT has chosen to do his sessions in blocks, then it is down to him to give himself enough notice and message the clients regarding the next block in a timely manner.

If he's had wierd vibes for a while then it cwas due to end. I agree with the pp who said he sounds like a control freak.
I wonder if he acts like this with his male clients?mmm

No people being ill is a general excuse which is why he doesn't like it.

She has acted wrongly in the sense of being inconsiderate in not warning the PT she was giving up at the end of the block. That should be signalled earlier on. Also, she has not treated someone else as she (and doubtless you) would like to be treated herself.
And he probably got no vibe that the contract would end since she says she gets on with him. He relies on the money so no wonder he is annoyed. I would be. Most people would be e.g. personal tutors etc who are in the same sort of relationship/employment. Notice may not be legally required but it is required by manners, and proper behaviour towards others.

It would have been nice to give him notice, after all it's his living and you have just said that you are not continuing with no notice of that fact.
That you pay in blocks doesn't make your lack of consideration for someone else, who is relying on income, any better.
How would you feel if you were told at the end of the month in a job that you had lost it with no prior warning? I bet you wouldn't be happy.
And if you cancel without notice, even if you pay, you are massively inconveniencing him - that your DC are ill is irrelevant, we treat everyone with respect, surely. Paying for a service does not mean you can behave badly to the people providing the service.
People on here will say you have done nothing wrong. But you have. You have behaved without consideration for another human being - you have treated another as you very likely would prefer not to be treated yourself.

We can tell, you bumped your post after 12 minutes 🙄

Why bother with a confrontation? OP is already ruminating on the exchange, making things more heated is not going to be pleasant for her.