[Visual77]

Assumptions? I agree that some parts are still locked at 18 but maxplayers is really caped at 32 on the server with l4dtoolz running and 18 with left4downtown running (This 18 cap on downtown can also give certain issues if you would run a 9vs9 server, due to maxplayers being 18 it can sometimes fail to create survivor/infected bots - maxplayers should always be larger than the amount of slots on your server to avoid this CreateFakeClient null issue.

For the record, I'm using 20 slots (maxplayers at 32) and I don't have any client crashes, neither do I have any server crashes - only the naturaly ones. I could stay on spectate over 24 hours if you'd like without crashing to desktop. You're right that the l4d2 server will eventually crash, run out of memory but that will take way over 2 days being straight full before that ever happens. So running 20 slots (maxplayers caped at 32) is no problems. Some servers are even running 22 slots but that seems to be were the limit goes. Going above that will only give you problems like the ones you brought up.

l4dtoolz using the maxplayers cmd on server.
"maxplayers" is "32"
"mininum_maxplayers" is "18"
"absolute_maxplayers" is "18"
"default_maxplayers" is "18"
"max_splitscreen_players" is "2"

downtown
"maxplayers" is "18"
"mininum_maxplayers" is "18"
"absolute_maxplayers" is "18"
"default_maxplayers" is "18"
"max_splitscreen_players" is "2"