30 minutes is stupidly short. I often tab out when I'm using the duty finder and watch something or cruise the net till I hear the sound effect. Having to stop every 25 minutes just to make sure I don't get logged is going to be annoying, assuming I remember.

Additionally I like to catch up on what has been said recently when I get back to the game.

And before you complain: I log out for sleep and for work. If it triggered at 2 or 3 hours it'd get rid of the sleepers and 24 hour logins and leave the rest of us alone. As is it's just going to get on my nerves if I lose track of time when waiting on the DF, relogging, re-queueing and waiting even longer will piss a lot of people off.