This is the first time I have ventured over to AIBU, please be kind 
I do a hobby in a large group, and have done for a few years now. I am also involved in the organisation of this group. We meet once a week to do the hobby, and normally have a couple of social events throughout the year. The latest one was this weekend and was a party in a pub. It was good fun, lots of people brought their partners or friends and we all had a nice time.
Throughout the evening I was vaguely aware that some people had a group bar tab going, but I didn't think much of it, and I wasn't involved in any way (I paid for each of my drinks as I ordered them). However towards the end of the night the barman pointed out to me that a lot of people had already gone home, but the tab was still pretty high. I had to do an announcement anyway that the bar was closing so it was last orders, and I also asked everyone to remember to pay off what they owed. A few more people did, but when everyone had gone home there was still £50 odd that hadn't been paid. I paid it, assuming that for most people it would have been an honest mistake and I could ask at our next meeting for those that had forgotten to pay me back.
We have now had our next meeting and no one has come forward. I know it is only £50, and I am not going to starve because of it, but I am not exactly swimming in cash and honestly I am a bit annoyed to lose it.
So would I BU to make a bit more of a fuss? Or should I just chalk it up to experience and let it go?