Originating from this question on Meta Stack Overflow (Question about the name of a software design pattern was deleted), we wondered why a specific question was deleted, which met all requirements for deletion, but had a bounty on it.
As Mad Scientist sums up in that post, a question does quality for deletion, even if it has a bounty on it.
Currently, the requirements for deletion are:
If the question is more than 30 days old, and ...
has −1 or lower score has no answers is not locked ...or...
it was closed and migrated to a different site ... it will be automatically deleted.
This seems undesired, even a bug to me.
Therefore, I suggest to add:
Doesn't have an active bounty on it.
This prevents questions with bounties on it from being auto-deleted.
(As a side note: Questions that have a bounty can't be closed without intervention of a moderator, so why would the Community user delete an open question in this period?)