The only IRC channels I've been in that have this policy state it clearly on the website. If it is clearly stated, I have no problem leaving the channel before I change my nick for away status. This policy doesn't really make sense, though -- I can understand banning someone who changes every few minutes, but for someone like me who's actually away (as in, I won't be there for a few hours or a few days or whatever), it shouldn't be considered spam. According to the logic, people should be banned for having a storm blow through and messing with there Internet connections. The only time I've seen channels ban for this is if they keep reconnecting for several minutes, then they unban shortly after.

I can understand banning someone for changing nicks just for brb status, but if they are actually leaving their computer for several hours or longer, I don't see a problem.

EDIT: If there aren't any rules stated on the IRC page (http://www.linode.com/irc/), people won't follow those rules because they won't know they exist. The rules for the IRC channel should be clearly stated.