Ctrl+w closes the tab, alt+f4 closes the program, and some people move their mouse to the corner of the screen to be sure it's out of the way (when such a feature would cause them to resign and there would be some confusion to deal with).
A "no escape" feature (like on ICC) would be useful to add to the seeks. This is where a disconnect is an automatic loss. A player is not given time to reconnect. Both players have to agree.
The down side to adding extra options like this is fragmenting the pool of available players, causing seeks to last longer.
There has been some concern about why people disconnect. Was it intentional? I think that's the question whenever someone dc's and doesn't come back. I have to say from my experience, its more of a technical problem. I'm not convinced that everytime it happens that it was something done out of spite, but it happens a lot. Honestly, I have a tendency to close the browser window with the intention of resigning the game. The solution I think is to make a link to the close command on the browser, so that if you move your mouse and close it, it will resign. How's that sound to you all?