I don't remember ever seeing anyone kicked, banned or even flamed for being a keyboard or mouse driver...
(at least not since ancient history when Scawen removed the keyboard helper code that made keyboard the fastest way to drive)
Mostly folks are flamed and banned for causing crashes, and making idiotic moves during a race...
If you join a server and cause mayhem, "It's not my fault, I'm using keyboard" is not going to be a valid excuse
If there are newbies (as opposed to noobs) joining a server, and having trouble, I would suggest that part of the admins job is to try and help them by explaining the basic rules and etiquette...
Any time someone new joins there is a point at which they will:
#1 get some help from an experienced LFSer, have some fun and join the community
or
#2 get flamed and leave with a bad taste in their mouth, never to come back - telling everyone who asks how crap LFS is
or
#3 get flamed and get angry and go on a wrecking spree
I would suggest that #1 is the preferable option, and it is the responsibility of the experienced racers and the server Admins to ensure that this happens as often as possible
It doesn't take much, and you gain bags of respect for doing it !!