Your wii wont be affected by crashes, because stuff like this cant access NAND. If it was something accessing your NAND, like a WAD installer or IOS updater, and it froze WHILE ACESSING YOUR NAND, then you could be in trouble. But homebrew games and apps do sometimes freeze, and you just have to hold the power button for a while to turn it off, then turn on again and everything is fine.
