Let's face it, we'll never agree on here. There are those of us who have taken school trips and have dealt with a roomful of gobby teenagers, then there are those who haven't, but know all the answers!
Sounds to me like yet another Andy Warhol moment, well done that concerned Mother, your 15 minutes are up I think. No doubt when your child turns round to give you a mouthful of lip in a couple of years time, you'll be back, blaming the schools for not teaching manners.