There should be a feature where if a player does not make any strat battle roster adjustments ever (basically is away and never accepts any one and sacrifices his peasants) that it auto accepts any pending applications. However, if any person who can alter the roster at all makes even one addition or adjustment, then the entire feature is rendered null for that battle. Thus, if the owner comes in and adds him self only to a battle, or if the owner adds anyone at all, then it will not auto accept at the critical moment.
The critical moment is simply the time at which the auto accept will occur. Perhaps it could be 5 minuets before the battle?