I get an answer for a question with a bounty:

Positivity of the alternating sum of indices for boolean interval of finite groups

The problem is that the answer came 2 hours before the beginning of the grace period.
The answer seems interesting and the author serious, but I will not have not enough time to check if it is really satisfying before the end of the grace period.

What should I do?
Should I award the answer just by the belief it is satisfying (but without being sure, yet)?