I saw this challenge which makes the following offer:
Note: A bounty will be placed on this question once it gets 10 upvotes
Although we discourage begging for upvotes, excessive self promotion, and certain misuse of bounties, I don't know how the community feels about a challenge author offering to place a bounty when a certain number of upvotes is received on a challenge.
I don't see any problem with sharing some of the rep gained from upvotes in the form of a bounty on the challenge, but stating this intention up front at the top of the challenge seems similar to begging for upvotes.
How do you feel about this approach?