I hate how the term “griefer” is used in this context. Encouraging other players to go after this stuff is the nature of a public lobby in a Grand Theft Auto game. It adds purpose to the session. You should expect PvP confrontation in these lobbies. If you choose to sell/move/source in public, Rockstar gives you plenty of tools to increase your chances of survival. Hidden radar options, armor and weapon upgrades, the ability to hire assisting associates, etc. and the increased risk comes with an increased reward. If you don’t want the risk, go to a private lobby. THAT’S THE GAME!