2. I would say don't promote any project without fixed payment in BTC or ETH. Their shitcoin can never get you a good reward, even if sometimes you get, it doesn't worth the time you spend behind. Don't participate in every bounty, try to promote one or two.
3. It's another method of dumping dev wallet, we just need to find it. Most of the times, hunters get trash.
Campaigns that pay with BTC or ETH are usually very limited participants so it is only natural that many people who join a bounty campaign pay with their project tokens/coins because there is no other choice but at least they try to research first before joining. If all the campaigns do that I'm sure many members will not complain and are more enthusiastic about promoting the project.