Rockstar is taking cheating very seriously in GTA Online. In a blog posted yesterday, the company said they have implemented new systems to catch cheaters more efficiently:
"As part of our ongoing commitment to combat cheating and griefing, we have recently implemented new systems to allow us to more efficiently detect and target any players found running mods and cheat programs within GTA Online."
They also remind players that if they are caught cheating by using mods, scripts or such, they will take some sort of disciplinary action against them. You might get added to a cheater pool, banned or even get you account revoked. Rockstar also posted guide on how to report cheaters if you happen to find one.