Think this kind of thing is what bothers me the most about this situation.The guy was doing is job, and actually giving a tit about the kids.
Years ago (the 80s) I took my kids away to Spain and this guy used to come around the pool every day and check everybody had sun cream on etc (and try and flog you some too) and one day my son was really burnt. A mixture of it washing off in the pool and me not applying it as much as I should of. Basicaly my kid, so my fault he burnt and the guy gave me a right bollocking in front of loads of other guests. What did I do? Deny all responsibility, say I didn't see any signs telling me to apply suncream? No I said sorry and that I was going to be much better at applying it etc. I felt an an absolute awful mum but it taught me a lesson.
There was NO admittance of “Ok, we messed up. Thanks for letting us know” There was just instant defence
No parent is perfect. While this is something I would’ve thought was common sense, obviously for them it’s not - but we can all learn. It’s like how some parents get SUPER defensive if you just mention something like loose car seat straps when they’re not being rude, just trying to help.