The Wii is a brand new machine that probably has a flaw or two somewhere. Someone did a post about possible vulnerabilities to be 'scanned', such as TIFF exploits used on the PSP.
Leave it to the pros to eventually find a way to run games through the network from a ROM on your computer someday, or transfer games like that.
Remember that Virtual Consoles games are more or less a rom + emulator, and that it can be saved on standard SD cards, so eventually someone will analyze that saved data and find the info we need.
And perhaps they will even manage to find the emulator code so that you could basically tack in any ROM you want to play instead of only those you can download.