When you sign up for a Forum game, whether as player or GM, you are making a commitment not only to the game but to the other participants. If you know that you are unlikely to stay the course then you should not join. It's easy to underestimate the time taken to play in the Forum - reading messages, checking results, and posting orders all take significantly longer than in main site games. And it is easy to underestimate also how long they will last. Forum Games typically last between three and six or more months; some have continued for over a year. If you can't commit that sort of time, don't sign up - you will only spoil the game for other players.
The same applies to GMs. Your commitment to the game and to the players is to see this game to a satisfactory conclusion. Be sure before you begin that you can carry it through to the end.
We accept that there are some unexpected and real emergency situations which cannot be foreseen. A long-planned, lengthy vacation, or the beginning of a new term at school or college, do not count as unexpected!