If you format you're wii it removes all traces. If you send you're wii in for repair they usually format it anyway. Also they don't even check for the homebrew channel my friend sent his Wii in under warranty with the Disc channel moved and the homebrew channel in place of it and they didn't say anything. I have also read through enough threads on _________ forums to know that Nintendo doesn't even check for HBC (at least not yet)

Its the same with M$ send in you're Xbox 360 flashed with the sticker still (heat trick) and they usually don't care hell M$ sometimes doesn't even care if the sticker is removed.