Unfortunately, no one from smartfox bothered to do anything about this. Quite frankly, I'm surprised that other developers have not run into this issue as well. You will also notice that the Java API hasn't been updated since Feb. 11 2009! I'm telling you this because I don't think anyone is going to fix this anytime soon.
However, all is not lost. We were able to implement a solution. I'm probably a little foggy on the details, but the gist of the solution was to have a different zone just for logging in, with a CUSTOM login. This separate zone doesn't really have any rooms. The custom login doesn't automatically try to send you a room list. Upon successfully logging in through the custom login, we were able to log the user into the desired zone. At this point, we send the user a fake room list that just has one fake room in it. It is necessary for the client to have a room list because most of the API will not function without a room list. We then added a custom extension call or two that the client could use to retrieve a custom room list. In our scenario, we actually know the room names that we want in the room list, so we can ask SFS to send us a room list with just those rooms.
The bottom line is that we were able to implement a solution where a room list was not sent automatically. And we added some extension calls to query partial room lists that the Android client API could cope with.
I hope this helps.