YeeHawBrimstonepugchamp would be 8 trillion times better if it had that join in 5 minutes or get a cooldown timer when pug info appearsjust get your captain to sub them
The point that I think Brimstone is trying to make is to encourage promptness to joining the pug. Sometimes you'll be stuck waiting for a teammate for over 5 minutes to join the server because they're finishing up an MGE or trying to complete a jump course and you'll either have to @ them in pugchamp chat or have someone message them on steam to confirm if they're coming or should be subbed out.
And just subbing people out at little to no notice from the captain (or your teammates to an extent) is a bit of a scummy thing to do, but there's nothing against doing it.