Exactly. It's an entirely different enviroment. The dumpshock guys and GMs like me get to happily work with the same 4 guys every other weekend and email their players with things like "Hey guys, if I change things up like this so you're not all just using the Ares Alpha and a machine pistol 24-7 you won't pelt me with doritos right?" and everything is cool. On a mux, you've got a rotating cast of people and making expectations and arbitrary rulings that don't even pretend to fix anything is either A. Crazy or B. Something that needs to be made EXTREMELY clear before people even set foot in chargen, and even then it's probably a bad idea. Which is part of why I think a lot of MUXers and guys who play through places like the Shadowlands.org have such a disdain for houserules- and dumpshock by extension. MUXes an entirely different enviroment from what most of the guys at dumpshock do, which is either play at home in an easily controlled enviroment or over a slowpaced play-by-post forum game in which everyone has ridiculous amounts of time to to pester eachother back and forth about rules.

This reminded me of something that seems a bit odd to me with the SR4 system.  You can't default from a skill to another skill.  I think if I was to houserule anything, I would allow defaulting within skill groups.  I think that seems to be the most reasonable way of managing it.