The aspect of people joing and leaving on a regular basis will normally allow a reserve slot to get in.
Lets say there are 27 people in right now.
"John Doe" drops because mommy wants him to take out the trash. Well he did not have a reserve slot, he dropped, and now there are 26 full. When he tries to get back on he can not due to the reserve slot.
If you ever get a chance watch how many people come and go in the course of a map. Some people leave and come back 3-4 times in the4 course of just one map.
So in that example the reserve slot person has NEXT DIBS on the next slot. As a normal person would get dropped due to "slot reservation" the reserve person would get the next slot, if it was at 28 slots full.
Reserve slots would guarantee your being able to play.
In the coruse of a map I have seen it get to 26 people. People getting the message about reserve slot every 5 seconds. (the server keeps a log of this) all of a sudden 3 people dropped and it is like a fight to see who can get that one non-reserve slot first. But then these people waiting suddenly see it go up to 27... "ARGH I should of gotten that reserve slot" they scream into the MIC as if it is connected to the server already. Well a reserve slot would of covered that the second they connected.
That is one reason that you will see an AFK get kicked for sitting more than 2-3 rounds. Keep in mind that just because you said "I gotta go pee dont kick me" The server console does not convert that to text and an admin watching the server, or a server variable, does not know this.
As we have all seen over the past week with the better ping many people , both regulars and new, have been keeping the server busy, if not full, between 4pm and midnight.
The server has had activity from 11am until 3am for the whole week. About 11am 4-5 get on and by 2 there are 10+, by 4 it is normally full. Around 2am it starts to go down a bit, the night crew comes in, it peaks again and gets empty around 5am. Yes there are off times/nights where people run because some one farted, but this has held true since the new server(s) have come on line.
This is on average 18-20 hours a day that someone is sitting on the server, a physical person.