I've noticed an uptick in failed login attempts on my site as well. I have to think that it is a bot, because a person should just get frustrated after a few attempts and give up. Attempting a brute force attack on a system that times out for 20 minutes after 3 attempts seems very foolish, but then again, just like those many repeated email password phishing scams, someone, somewhere takes the bait or uses a simple password and the default user name.