To be annoyed that DCs were left unsupervised in the swimming pool

[olimpia]

So an ex colleague of mine invited my two eldest boys, aged 10 and 8 to stay at hers for a sleep over. She has three girls aged 12, 9 and 8.
Today when I picked them up she mentioned that this morning the children went swimming while she and her DH ran some errands in town. She said that her oldest DD was looking after them meaning that she was "in charge" I guess. I wasn't impressed but didn't really say anything as I was picking them up after they had been at hers for 24 hours so didn't want to sound ungrateful and rude.
When we got home the boys said that she dropped them all off at 12.30 and said she'd be there at 2.30. She gave them a packed lunch. Turns out that after 1 hour or so they were all hungry and they decided to get out to eat. The pool doesn't have a cafe so they ended up having sandwiches in the reception area and then they decided it was too late to get into the pool again.
They were picked up late at 14.45 so they were left waiting again unsupervised in the swimming pool's reception for over an hour! They can all swim ok but the pool has a deep end. Five children aged between 12 and 8!
I'm not happy at all! AIBU?

OP: do your children face a raised abduction risk for some reason? Or is there a reason why they would need closer supervision than other kids their age. If so, YANBU. If they're just regular kids, they might benefit from a bit more responsibility and trust.

YABU.

The only thing I would be is giving the a packed lunch, I never let the DC in the pool until 30 mins after they've eaten (maybe IBU about this). So I wouldn't like the idea they could have eaten and jumped back in straightaway. She should have brought the lunch with her when picked them up.

They chose to get out and spend all that time in reception, so maybe she should have given them clearer instructions, but no harm was done and the only problem I can see is them irritating the staff, can't see why them having to wait is a problem, it was their choice.

Not sure about this. You agreed it was ok for the 12 year old to be in charge. She kept them altogether, they didn't leave the building and parents turned up within a reasonable time. Our pool allows 8 year olds in without adults. Not sure what the AIBU is about.

YANBU I didn't let ds1 & 2 go swimming alone at that age. Lifeguards are there to watch everyone they are not there to keep a special eye on your children. That's your job. A boy drowned in our local pool - by the time a member of the public noticed him and the lifeguards pulled him out it was too late. If she asks to have them again I would decline and let her know that your ideas of childcare are too different.

I know 8 is allowed, but it is marginal for over 2 hours and wrong without parents express permission.

Most DCs will swim in a group for up to an hour, but they are then going to get restless. Just like these DCs decided to get out and eat.

It's not fair on the DCs or the pool staff to leave them that long.

She probably assumed you wouldn't mind because children are allowed in a pool without an adult at 8.

There may be weirdos hanging around that park

You seem more than a little obsessed by the idea that paedophiles lurk around every corner waiting for a new batch of children to be delivered. So actually, I think your reaction to the park idea was probably OTT.

So far as swimming was concerned, the choice to sit in the reception area was theirs. So they weren't exactly abandoned to their own devices. I think I might like to have known they were going swimming but at the ages quoted I would have assumed they should be able to cope. Pools employ lifeguards for a reason, after all.

I suspect you might be better off avoiding sleepovers with this particular ex-colleague though since your parenting styles are clearly very different. Note that I say different. Not wrong.

However, I do think 8 is a bit young to be left in the circumstances you describe.

Yanbu