No. A lot of people come here to get permission to do stupid things, and they would punish people who do not give them permission, and if that punishment made it harder for people to get Amazon gift cards or whatever, then that would incentivize people to give permission to people to do stupid things, rather than giving genuinely helpful advice.
No I don't, their is enough drama on G@G as it is with down voting and their as always the possibility of giving least helpful just because you don't like the user or if some one fails to give least helpful after a certain amount of time, gag would automatically choose least helpful like it does when you don't pick most helpful, and gag system could make a mistake and give the answer that truly deserves most helpful least helpful.
No. That would only cause drama and hurt feelings. There's no point in bringing about more negative energy to this site. I could also simply see people abusing this feature and choosing a user they dislike for "least helpful" even if that person gave a good, well thought out response. It would just be a bad idea all around.
I think you mean as a joke or something, right? In that case it might be funny in my opinion. Like they do just opposite of Oscars. But i think people might get offended to be honest. Most people are very sensitive about those things and it might cause a lot of drama. No need that.