I completely disagree, mIRC, or any IRC client here, should not change these kind of value given by IRC server. I just don't understand why there is a limit on this value, I would like to see this limit removed, not extended.
I don't understand why it's called a sanity check here, what's insane about accepting the value from the IRC server, even if it were super high like 4500? You can call this value non sense, you can easily argu that the IRC server shouldn't be using such a high value etc, but you should accept it.
Extend it to 30 today and tomorrow I'll report that my IRC server use 31 (unless there is a good reason for such a limit that I'm currently missing, of course).