Gentlemen!
It has came to my attention of playing AoS for a full year now,seeing n00b after n00b doing this, that there is a new phenomenon on our hands... I want to be the first to coin the term, TF2 Spy!
TF2 spying is when a player switches teams to the oppositions, griefs their structures (as spys do) then switches back to original team thus gaining the upperhand. it's stupidly annoying, it needs to stop.