i don't get it

this week we run a holiday program for children who were at kinder last year and are heading off to school in a week or so. this morning one of the children told my co-worker that his water bottle was filled with cordial and he wasn't supposed to tell us (we only allow water at kinder because it's much healthier for teeth and body than the juices/cordial that a lot of them would probably bring). near the end of last year his mum had given him cordial one day, which we told him he could have when he goes home and we gave him water for the day. his mum is a pretty sensible person so i'm not sure why she would give him cordial again, knowing we don't allow it (and i'm sure she knows water is much better for him)-- especially since she told him not to tell us (and every 5 year old is going to tell us things they have been told not to tell us, that's what they do). it was a HUGE bottle of it too (if it had been a tiny drink bottle that was in his lunch and he'd had a separate water bottle for the day i probably would have just let it slide since it is holiday program and these children are heading off to school where i'm sure half their lunch boxes will be filled with the junk that we discourage at kinder. i don't get why a parent would do that-- it's not helping their child out at all and none of them have any problems drinking just water at kinder. it's good for them.