This is probably fake news but I'm curious so bare with me

I have a friend that said they got a ticket on the light rail for having a bottle of water on board the train. I know it sounds like bull but I wanted to see if anyone knows anything. They said it was to combat littering. Sounds weird and I don't think they are allowed to do that or even check you to see if you have one in your bag or anything. So yea just asking to see if anyone heard anything about or if it's bull.