1. Its not every time we will have something to contribute on.
Most times i come on here i only see old posts that i have no interest in at all but due to meeting up with required bounty posts i will be forced to complete them, some posts are so useless or repetitive that you won't want to say a thing
You have applied to the signature campaign so you have to comply with their demands so you can earn a stake every week. And if you can't do that you won't have to wear a signature and no bounty manager will adjust you.
2. This is another way to reduce spammers, few bounty managers i knew of will only request 7 to 10 posts per week which i feel its more than enough, moreover we have too many scam projects in this space already so not every bounty projects have guarantee
It does not help to reduce spammers. Because spammers will not disappear and they will continue to do so.