As you know, a lot of bots or people got dynamic IP addresses, and this could mean that the Baidu bot you banned recently could eventually return.
Well... I wonder if it actually returned already? Because in the past week or so, the online user count seems to have slowly been going up again, even though we're supposed to be in a quieter period (and in fact it's quieter).
You might want to check that out, in case this cause site slowdowns again.