I've always loved this too. One thing I see is "retaliation" from other teams often. KG will knock the ball away on a dead ball on one possession, and as soon as someone on the C's tries to take a shot on the dead ball during the next Celtics posession, a player on other team will try to knock it out. I personally love this, it adds a little competitive spark/trash talk element to the game that the league is trying to eliminate.
On the same note, I would not at all be surprised to see the league outlaw this saying it is unsportsmanlike conduct. Goaltend on a dead ball and it's an automatic T, I would absolutely hate this but I could totally see the league going in this direction.
No free shots for anybody, not when I'm on the court. I totally love this mentality, not just from KG, but from Ricky Davis, Scals (who I've never seen do it, but it would be extra cool if he did it) or anybody else.