What do we do when a reward amount changes while someone is already working on the bounty?

[ElliotFriend]

Example: #113

Specifically, when is the old reward honored? When is the new reward given? Some scenarios might be a bit more obvious than others:

• If the amount changes the day after someone claims, it might make sense for the new amount to apply.
• If the amount changes the day before/after the reviews begin, it might make sense for the old amount to apply.

What if the work is halfway(-ish) done? Does it matter if the change is an increase or decrease?

Not necessarily looking for solid answers, but more of an opportunity to flesh out some ideas and discussions and garner feedback.