As people have mentioned before, it all probably comes down to the particular technician handling your Wii.
I work part time as tech support for the major ISP here in Sweden, and have people calling in all the time having problem setting up their torrent/P2P/whatever client and the like. Of course it's not company policy to promote and assist in piracy, but I still help each and every one of them set the app up.
I suspect a whole lot of people working at Nintendo mod their Wii, one way or another. Also, even if they didn't sympathize with homebrew, fixing your Wii out of warranty for free when you've fucked up yourself makes you
a very happy customer. They probably just react: "w00t, here's another dumbass who couldn't follow an idiot proof tutorial and got a brick. Muhahahahahahaha ... well well, let's fix it for him."
Techies aren't less human than others. Hell, I swap modems for free even when I know the customer himself have broken it by barfing in it while drunk ... (It has happened ... and it was ... the cat who did it ...) I can't promise that I wouldn't ridicule you during my coffee break, or save a recording of the call for my personal enjoyment, but at least
I would probably help you even though I'm not supposed to.
A happy customer buys more stuff from Nintendo in the future than an unhappy does. A happy customer recommends N.'s products to his buddies which is better than
any PR money can buy. Seeing it like this makes the decision of helping peeps with the torrent clients as mentioned before very easy to take (particularily since we sell a subscription - happy customers pay for waaaay more months).