USCF

I don't believe you are even allowed to touch your opponents pieces , except to capture them. You are supposed to ask your opponent ( only when its your move ) to adjust his piece(s) if any need adjusting . 

What you are witnessing , I believe , is the slow death of adult chess in the USA.  Tournaments seem to cater , more  and more , to scholastic chess events . There seems to be no effort to keep adults playing , or to attract more adults to chess . The fact that adults do have to play with so many kids that are ill mannered even causes some adults to stop playing .  I recently had an incident with a player of about 10 years old , when his position was lost , and he realizd it he started offering me a draw every other move or so . Ofcourse, I declined but he kept offering and after about 3 such offers I could take no more and I ordered him to NOT offer me another draw .  In this same event I witnessed another scholastic player with annoying behavior that was present only when it was his opponents turn to move ....   I don't mind playing with young kids as long as they know the rules of the game as well as proper behavior during the game .  Otherwise , I would prefer not to play them..... let them play among themselves until a certain age , or a certain rating and also dont have scholastic sections in the same room with the adult Open events .... this is also a big minus when this is done imo .