that really depends on what bounty you are signing up for. not all of them are same. Some of them turn out to be a scam while others are legit that distribute on time and consequently their project does well after launch. I would say most bounties distribute except may be handful that get mixed with them.
Just look at this thread most people agree that 90% are scams and I think they are run by the same people most of the time. We need to stop this from happening.
those who have successfully scammed the bounty community and their early investors through their new projects. of course, they won't just walk away.
after enjoying the benefits for a while, they will come back with a new project again and will commit fraud again. and there is always a cheat for all of it.
nowadays we are seeing more and more scam projects, and there is no way to get around this.
if you are thinking of the best way to regulate new projects with more decent bounty payments. maybe it will get support from many bounty hunter communities.