Age Discrimination At Playland

I realized today that McDonalds is guilty of ageism. 

I have read the same sign a thousand times but it didn't really sink in for me until today. The sign says that kids up to 12 can play....and parents too. But what about those from ages 13-not yet parent?

I am surprised that they have not had any law suits leveled against them for this. 

What if, say, a fifteen year old was already a parent and they were able to play in there with their child...but another fifteen year old who went with them was not yet a parent? Would they be excluded from being able to play? And by what right?

I ultimately don't care. I am personally afraid to send my kids to play in that diseased ridden excuse for a good time. They might have fun, but I'm afraid of what they are going to bring home.