I believe he is asking is it "team grieving" if you are on a friendly team & squad, with someone in your squad having a well hidden beacon. For whatever reason Squad Leader kicks you from that squad. You switch to the enemy side, then go immediately to where the beacon(is located), of your previously kicked squad, and kill them & beacon...
Correct me if I am wrong..
Yes it is a complete bitch move, as previously stated, and yes it would be grieving.
You switch to the other side, because someone kicked you from a squad, not withstanding, just going to another squad, on the same team.
By those actions alone, the previous SL, probably had good reason to kick you.
IE.. Shooting from the location of a well placed beacon(after spawning from it), revealing your squad, and more than likely the beacon. (idiots & noobs do this constantly from moving vehicles, often revealing their positions) For no reason at all.