If you see this happen, please write in to our support team; we take data integrity issues very seriously.
Also I should probably mention that we keep 1 month of version history for free users and even more history for paid users, so if the corruption is recent you should be able to undo it yourself. But please report either way.
I'm a huge fan of Dropbox and I pay a monthly fee. I probably don't need to as my data needs aren't huge, but you guys are frankly the first people I've used that did this sort of thing properly and I believe you are worth paying a subscription fee to.
I'll log a ticket :-) might need to reproduce the issue first. Pretty awesome that you have employees who respond to posts on HN incidentally, that automatically increases my loyalty to a company several notches!
Also I should probably mention that we keep 1 month of version history for free users and even more history for paid users, so if the corruption is recent you should be able to undo it yourself. But please report either way.
(Full disclosure: I work for Dropbox).