Yea, not normal at all. My 6 year old would NEVER act that way. It wouldn't even cross his mind. Nor would it my 8 or 4 year old.
We went to visit my sister over Columbus Day Weekend, and my mom's neighbor and her youngest son (10) also came...I nannied for him and his older brother when they were little. Now my interaction with them is mostly when I'm at my mom's house in the warm weather and all of the kids are playing out back.
We went to breakfast and the kids cups were styrofoam. As soon as my son (6) finished his milk he asked for a refill. Once his new cup came, the 10 year old took the old cup and started to break off and EAT the cup. Yes, I said EAT it. I was mortified, embarassed, and even more disgusted when his mom laughed about it. Ugh.
The next weekend we took him to Virginia with us to a battle reenactment and I've never in my life seen such manners from a person. HORRENDOUS.
Some people just aren't raised by people that care, so the kids don't know any better. It's sad.