I've name changed because while I don't think I'm BU I've never posted my own AIBU before and quite frankly I'm terrified if this all goes wrong for me. But I digress, on to the tale of woe:
Nice day here today so DS (3) & I decided to go for a very exciting long walk to the big supermarket on the other side of town. While we're getting ready to go out DS was playing with my purse, taking out coins and putting them into this little purse his gran gave him. I checked and he'd taken about £3 - £4 in pound coins and 20p & 50p pieces. He then put his purse in his backpack and told me he would pay for the shopping today. So far, so cute.
Got to the shop, wandered around, picked up a few things then went to pay. At the till there was two staff members, one on till, one doing something else. DS charms them both by chatting away and I get bags ready, get my purse out to pay and try and clear up for both of them what DS is talking about.
The staff member not on till asks lots of usual questions about DS and I answer as I put the shopping in the bags. Then I notice DS and the till lady are counting something out and I think "oh, he's trying to pay the lady for the shopping" but when I look to see whats happening (yes I was distracted although he was next to me) I see the till lady holding a charity collection tub towards DS and she's helping him count all the coins from his little purse into the tub.
I told him to stop and had a look at what was left - just the 20p's. I must have looked at the till lady like this 
as she just shrugged and said at least it was for charity. I looked at the woman I was taking to and she said something like "aww, at least it's for a good thing, not on sweets" (not verbatim). I stuck my card in the reader to pay and finally said I didn't think it was on the encourage a 3 year old to put all their money in the collection tub without asking their parent if it was ok. The woman on the till said nothing but the other one said (head tilted to the side and sounding sympathetic) "I know, but it is for charity" (that is verbatim, it's burned into my memory!)
I scoffed and left with DS, him asking did he pay for the shopping. I said yes.
So, AIBU in thinking you don't encourage little kids to put money in charity collection boxes without asking their parents first or does charity trump everything?
I know people will say I shouldn't have let DS keep the money. I know if it had been lost in other ways it would have been my fault but what happened today feels like it's been taken from him under my nose.
And yes I wasn't given him my full attention but he was at my side, I thought he was just talking to the woman.
The worst thing is I didn't even look to see what charity it was for. Knowing my luck it will be something dumb like a doll museum 