I can top that....we were waiting for PTN a few months ago and I had bought my 4 YO son a light-up Mickey staff. There were two kids sitting behind us that kept insisting he HAD TO SHARE it with them. They kept trying to grab it and take it from him, and then crying when I wouldn't let them have it. I was seriously annoyed. I finally had to take it away form my son and not let him play with it, even though I'd bought it for him, because these kids thought they were entitled to what he had. I couldn't figure out who/where their parents were....finally, the boy one last time tried to get the toy and said "he has to share"....and I turned around and said "NO! HE DOES NOT!" and the kid left him alone after that.
But seriously, if you're at my house as a guest or on a play date, then yes...my son should share his toys with you. But a stranger in a park who wants something that I specifically bought for my son to play with? I don't think so! Go ask your parents to buy you one....you aren't "entitled" to anything you want.
Man, I was pissed.