Yeah, that was my immediate reaction too..
A little more seriously, this happens to me sometimes too - waiting for a minute or so, or closing and re-opening LFS, tends to do the trick. Restarting LFS probably makes no difference at all but it keeps you occupied in the time it takes for the master server to discount you, I suppose
But did this particular issue go on for longer? Because it might be someone a bit weird if it was more than a couple of minutes.
Sam