I haven't found anything on the Internet about this yet but this is a particularly annoying problem.
I have troubleshooted a couple sites that had a couple users reporting their their accounts were getting locked out of Active Directory every so often through the day, meaning that an administrator had to keep unlocking them so they could keep working.
After quite a lot of troubleshooting I deduced that this software, LogMeIn GoToMeeting, is the cause. After uninstalling this program on the affected user accounts no longer get locked out throughout the day.
Mostly posting so other people with a similar issue may find a solution, but this should really be fixed.