No server should have more then 4 bots. And they should be removed one at a time as soon and humans show up.
Why though? They're marked as bots in the server browser, and playing against only 4 bots on an empty server is way more boring than playing against basically a full team.
 
-1

you already know why
its called people getting bored and leaving the server faster because of no bots
 
The bots are already set to remove themselves as the server fills up with players. They just keep company while there is a low player count.