When you log in the default format shown for the ladder is SV Random Battle. If you are laddering and disconnect, its pretty easy to just click "Battle!" without changing the format and, since you don't need a team to play Random Battle, the battle will be created and you will need to play or forfeit a match you didn't wanted to create. My suggestion is just that the Default Format shown is changed from Random Battle to the first favorite format. I guess people with multiple favorite formats would have issues since the favorite formats are ordered alphabetically, but it would fix the problem with most people.