For an antique version I have no real clue and no way to do any sort of investigation. In general though I'll say your hitlog will have a heck of a time figuring out what's what. Or maybe not...

Heck it might be no problem at all for b2evo to deal with it. As long as $baseurl was set correctly of course. Anyone with an account set up at one path to the database would have to log in again on the other path if they wanted to use it - I think. This due to what the cookie says about the login yah? But for the most part I can't really see where "wow you should never do that" would be a valid statement.

It could get a little funny to be editing a post on one path when someone else deletes it on the other path then the first person saves the edit. Dunno what would happen then. But I can't off the top of my head think of a situation where it'll mess something up.

Do play it safe and have a backup handy - just in case ;)

Hey I just thought of something. I've seen two different domains name using the same database, so heck yeah it'll work. We cut that low-grade spammer from the front page "updated blogs" list because that was a pretty cheap trick, but technically speaking sure why not.