Not often, but regularly, people disconnect from games as a form of resigning, and I have to wait 5 minutes to force resign them. I just had an opponent type "have to go" at the beginning of a game and then disconnect. I have no reason to expect that this is done out of spite---almost certainly they just don't understand that closing their browser window doesn't automatically resign them.
So my proposal: when you disconnect and are force resigned, the next time you login there should be a message that pops up and explains that you were force resigned and that disconnecting is not resigning.