Hm... an inherent problem with bounties in general. If the other people have their solutions posted in the replies, at least on stacker news it's easy for anyone to reward their favourite responses.

Clean bounties with no modifications have their perks though, their simplicity is valuable and has stood the test of time. Any modified version I think ought to be an optional setting.

One optional setting could be; "Top three bounty with some kind of distribution equal or 50/30/20 for instance" Then the top three bounty system could require the OP to select & rank three replies in order to do the bounty payout. Maybe a setup like that could even encourage more people to help?

Always interesting to explore new ideas and functions :) Game Theory problems are fun.