Tbh, you hear teachers complaining about lack of parental involvement. I would have thought having family there would have been positive. I can see your point about being a social gathering though. Does defeat the purpose.

I was super into athletics in school, we all had parents there cheering and supporting. In fact my grandfather would be doing my post race rub downs (former footy coach). For me having my family there was important. I knew they were cheering me on and proud of me. I always ate with them because mum had the right foods for me and its not like I ever ate with them normally at school...

I think the line could get crossed though if family detracts from the even instead of improving.

Fwiw I would be peeved about the milk down my back too