Quite honestly your post is one of the most stupid things I've ever read. You're saying 5 guys, three of which have to be residents, have to defend the city for three days straight at peak times? You're literally asking for 5 guys to hold off an entire army three days in a row, for hours on end. Realistically, the couping force could bring as many outside allies as it wanted to secure the city.
Edit: Also, what if the leader logs on for 10 or 20 minutes then disappears, but he does that everyday therefor you can't catch him nor is he active.