Every time I loose mercs, it's because of some annoying bug. Wouldn't it be simple to have mercs use a radio when their master is gone? Or to just automatically make a DOT when you leave them? This DOT would only last 5-10 min, and after waiting to long, the mercs just wander off and you loose them, but atleast we have a chance to go back and recover them! This way there is no more accidentally "leaving" them forever...