For those who still see cheaters in a lobby putting large bounties on other players don't fret. I believe Rockstar has possibly put a fix on the hacked bounties.
When i first logged on today I noticed my bank of 4 Billion was reset to a merely 1.2 Million. Seeing this and realizing Rockstar actually fixed the game i left my apartment to see if anything else has changed. While I was exiting my apartment a notification popped up saying I have received a bounty. When i first arrived outside I checked to see how much and what do you know, $200 million bounty.
Seeing this I backed out and proceeded to wait the hour in a private session so i could be rich again whenever i switched lobbies the message saying i had a bounty put on me stayed so i know it should have worked. After an hour of waiting it said I have survived the bounty and received $9,000.
My theory is that Rockstar did not block being able to put large bounties on people, they blocked receiving the reward! And to see if it could happen again, what do you know another bounty of $2 billion was placed on me, i left and joined my friends private session and he killed me and only received $9,000 aswell!
Good job Rockstar!
tl;dr - Got a hacked bounty, only gave me 9k for surviving the hour.