It could be abused if it is just for killing.
For instance, Bill put a bounty on Todd. Jack, who is Todd friend, kill Todd, get the bounty and share it with him.
Could be moved into :
Bill put a bounty on Todd. Let's say 1000 caps
Loyd register in the bounty hunter faction. Look for available bounties.
Loyd get a rope, and start looking for Todd.
In each town, he can ask a specific npc, when was the last time Todd was there (ingame days or hours. More than a month is like never) and which exit he chose. (or if he just disapeared)
If Loyd can't get Todd an ingame month after Bill put the bounty, the money is lost and Todd is no longer in wanted list.
If Loyd manage to get in seven place in which Todd was less than a week a go, or one place in which he was less than a day ago, or if he actually meet him, he will get a signal of that guy.
This signal will apear for an ingame week, and will show the coordinates of Todd.
If Loyd manage to kill or knock incouncious Todd, he can put a rope on him, like a slave.
Then a bounty hunter npc will appear and teleport Todd and Loyd to the prison facility.
Loyd will get his money, and teleported to the front door of Bounty hunter agency.
Todd will remains locked in the prison facility, for one ingame day, for each 100 caps spent.
As the bounty was 1000 caps, he will stay 10 ingame days. The bounty can't be higher than 100 000 caps.
If Jack still care about Todd, he can give the Bounty hunters some caps to make shorter the prison sentence.
If Todd already stayed 5 ingame days, Jack would have to pay 500 caps to get Todd back free, plus 10% fee. 550 caps in total. The % fee can be dynamic.
Next time Bill will check the bounties, the bounties hunters would say to him, that Todd was caught and sentenced.
Of course, it is still possible to be brutal and attack the prison facility, but the team who do that would have to face endless respawning guard, to shutdown electic generator and lockpick the cell doors. Plus all people who do that would have bounties on their head for that. (100 caps)
It is also possible to have bounty on his head if going - 10 000 reputation with a faction.
Todd also can be chased by an npc with the same level as him, instead of Loyd, the player.
There is maybe too much elements for a so limited features.
Just bringing ideas...