I can call in the tank at any time like a lot of you. I had a brief cop murdering rampage in it... and then I was done with it. I didn't want to be one of those tank players who traverses the map looking for blips to annihilate, I think that's kind of pointless. As a relatively high-ranked player, it's my responsibility to not ruin the game for the lower ranking people who have yet to experience everything GTA Online has to offer.
Therefore, I am now going from session to session collecting my tank and parking it near a lowbie. Instead of exploding them, I beep my horn, get out, salute to them and walk away. The tank is theirs to do what ever they wish with it. Hopefully they can appreciate it and have more fun with it than I would.
Perhaps I'll enter a session where a high-ranking player is causing chaos with his or her tank. That should give me a chance to unleash a lowbie onto them with my tank. It's about time the defenseless had a chance to get back at the glitchers and so-called "elite".
I urge everyone in my position to do the same. More often than not, the player who receives your tank is very grateful and they will restrain from firing at you out of respect. If, however, they don't do that, you can always make sure to stay in Passive Mode. Failing that, if a low level player is as bad as the high level tankers, get your Sniper Rifle out and get things under control.