Would you pull a sickie for a pre-booked trip?

I wouldn’t. I’d feel forever like I’d be found out.

Also, how will your Saturday be covered? Will one of your colleagues be called in to do it at short notice, ruining plans they have?

They should have just banned Julie really. Once she'd swapped it was on her to find someone else who was not Ann.

Where I work 1st 3 days of sickness are unpaid

Lazy management! One issue and it’s banned.

But now they’ll have to cover sickies, shame they’re so short sighted,

I agree with you. One can't even say that the OP knew the deal when she took the job because at that time you could swap Saturdays with others.

This! 👏

Which then makes the system unworkable! Doesn’t it!

Sorry SIL you should’ve checked which date suited me for your wedding, it’s the most important thing to do! Yes, you may have only been able to get the venue for that Saturday, but as I’m running the country that day, I can’t take it off.

Oh no, not running the country working for an inflexible employer, who doesn’t pay sick leave.

If you can afford to be unemployed, crack on. Because you'll be at high risk here of disciplinary action, pregnant or not. In fact it could be the perfect excuse to get you out the door.

If you can't, tell your partner to sort his mess out.

I would have said go for it, it's a one off and was a mistake... Your employer wouldn't think twice about making you redundant!

But it will be absolutely obvious to your manager now that you've asked to swap. They will be hyper vigilant because it is a Saturday.
It would be a gross misconduct if they find out. If you're counting on maternity leave, I assume that now isn't the best time risking losing your job.

In this case the employees need to get together and petition management to change the system. Maybe you could ask for rotas more in advance, ask to be allowed to swap in exceptional circumstances or something like that together. Or just find a different job if you don’t like it.

But it you resign or get sacked bear in mind that you probably won’t qualify for enhanced maternity at the next place, even if you managed to get a job when pregnant, as you won’t have been there long enough.

Inflexible, blanket ban of anything for a kick off - we had to ban this thing because too many people were making the managers lives too difficult - type energy, like we're children. I prefer my employers to treat me like an adult, that has real life situations that can happen.

No boss I have ever had would have been arsed with all the faff of a disciplinary, when it's an otherwise good (and pregnant) employee, over one day. I would do it.

Id start making ill noises on Thursday pm. Lay it on Friday morning and throw in a few "think ill be in bed for 9pm im not feeling right at all" in the afternoon if appropriate chatter arises. Then possibly leave a bit early on friday due to illness.

Pregnancy related of course, morning sickness etc.

This is really shit and I don’t like the sound of your employer but unless you’re prepared to lose your job over it, and the reality is discrimination is rife so it won’t be easy to get a new one while pregnant, I wouldn’t go. It is far, far too risky.

No, by evidence I think evidence at the time. Like an email or text from the doctor confirming an appointment, or from a midwife or something like that. It would all depend on the reason given. If OP
says she had a midwife appointment or had to attend hospital there would be contemporaneous evidence of this. But as you say, if it was norovirus used as an excuse but after a days leave and when the employee had asked for the day off already it may not be possible to get evidence, and so all the employer might be able to do is make a note of the suspicion and keep an eye on things. But in this situation I would not expect the manager/ company to be extending goodwill the other way and if the OP genuinely is ill a couple of times in my work this would trigger enhanced monitoring where (I think) you have to provide evidence every time you are off.

Banning swaps does sound a bad policy though, esp as you only have the shifts at such short notice. They should give you much more notice any way.

I think your partner needs to try to swap the booking. He messed up, he needs to change it.

You shouldn’t have to risk your employment by throwing a sickie or mess about - he needs to change it. It’s not for him to “tear his hair out” - he just made a mistake and needs to change it.

If the first few days of sickness are unpaid then staff are going to be careful not to take a suspicious number of odd days off especially next to a weekend. You learn to be strategic in these matters. However employers who have such rigid rules will reap what they sow.

Why are they shit employers?

Shit employer so do a sickie

You have a point here as @VickyEadieofThigh has bluntly pointed out, the employer doesn't sound great, so fck em - they're not going to take care of the OP during her maternity leave I suspect.

Not really, first 3 days are unpaid...... You expect employers to pay the odd sick day when it appears from here that many are taken when not genuinely sick...?
If every employer paid for every sick day, it gives people more excuses to 'skive' off.

So OP goes to the doctor and says I was sick last Friday and Saturday, employer wants proof. What are they going to say? No, I’m not doing that? You didn’t have a bug?

it’s a pointless exercise and I’m sure OP would get the “proof” she needed