ID:1599815
 
Not Feasible
Applies to:DM Language
Status: Not Feasible

Implementing this feature is not possible now or in the foreseeable future
"A ban that applies to all worlds on the host's computer will not call IsBanned(). The connection will simply be denied."

Pretty much just requesting that IsBanned() is called regardless.
This has been discussed several times in the past, and shot down. Here's some of the previous discussions:

http://www.byond.com/forum/?post=133701 <- Probably the most thorough discussion
http://www.byond.com/forum/?post=133803
http://www.byond.com/forum/?post=133989
http://www.byond.com/forum/?post=134046
I don't see the problem in IsBanned() calling anyway. I mean, what's the harm in checking if a person is banned? It's more a case of a simple solution, rather than forcing the game to be hosted in trusted and using shell() to locate the ban file and check. (Unless of course you have any alternate solutions?)
Alternate solution: Don't care so much about what private servers of your game are doing and worry about managing it on the hub like every other author.

As stated in the previous discussions there's a very good reason for it working the way it does.
Nadrew resolved issue (Not Feasible)