In my case it was not the words sent but the action and intention behind them. A while back I was running the Weekly Heroic (after matchmaking was implemented). One of the players was dead in a bad spot so we could not revive him. So only 2 left. When we were about to kill the Archon Priest that guy who was alive w/ me sent me a msg and invited me to join on his Fireteam. Since the guy was playing nicely I decided to join him. He immediately booted me and joined a friend of his so they got the rewards after me doing all the work. The same guy who died many times on the first stages of the mission and got revived by me. I sent him a msg saying: "How do you do that man? That is so dirty..." He replied: "Love you too Bro. LOL." Since then I only join Fireteams with folks I know.