It's been a while since I posted in this thread, but this thread is STILL right at the top when you search for "Gaim auto accept" on Google
The bottom line is, Gaim's auto-accept plugin does what it does well - but it doesn't do very much!
I've made a modified version of the plugin that allows you to auto-accept from anyone, which is a requirement for my job - read the article and you'll see why:
Ben XO » Blog Archive » The triumphant return of Auto-Accept!
(also has the plugin for windows and a patch for other OS's on that page).