My main intention is to use a modded rules when playing on LAN, where me and some friends use the same rules.
In the original Westwood release, I seem to recall that local MP applied the rules in the same way as SP skirmish. It just denied access to MP games if the rules weren't identical.
Does the same thing apply to cncnet (with spawn.xdp and spawnam.xdp) in that it just denies game access or does it deny access to cncnet altogether?