I Recently upgraded my Slackware installation to 10.1 and started using GDM as my display manager. Turns out that GDM is pretty nice, I have even been messing with making my own custom theme!
Anyway, today I came across something VERY odd. I have a password policy in place that forces the users on my pc to change their password every month (plain good practice). However, since installing 10.1 I had been aware that it seemed like a long time since I had been informed of my password expiring. Today I switched over to another console (ctrl + alt + f6) to kill a cedega app that had frozen, to my surprise, when I tried to log in I got a message saying "Your password is inactive. Contact the system administrator". Then when I logged out of my X session and tried to log back in my password worked! So basically my password HAD expired but GDM would allow me to log in anyway!
I didn't post this in the "help" section because I'm not really looking for a solution (I just going to switch back to KDM) but I thought it might be worth informing anyone else that uses GDM of the problem.