Everyonenow and then uses the stay command (S key) so your unit(s) do not wander off. I think when you use that command the unit should be able to defend the spot its given. You watch videos of battles within your base or play backs from batt fights and the units you have given the S command to just get shot up and die . Think this would be a nice to have, you pay for these units with a lot of res would be nice if they fight without having to be moving.