allow negative “Manual download count”

I would like to request that the handling of the “manual download count” be modified to allow one to enter a negative number. Right now, it strips the negative sign when saving. If I modify the entry directly in the database, it uses the negative value correctly to compute the total downloads, but if I ever save the download post again, it will strip the negative sign.

FWIW, my reason for doing this is to provide a negative offset to the count to eliminate counting a batch of “downloads” that I determined were from bots.

Any other tips/best-practices on preventing bots from downloading my files and inflating the counts would also be appreciated. Right now, I’m just using the “Blacklist user agents” to catch a couple of obvious ones.