I don't believe hacking/seeding will be a problem in AC for the
wii. Mainly because its a disk, not a cartridge (on the
ds version, anyone who entered your town had direct access to the games programming, and since the
wii cant burn disks, this will not be possible on the disk). Lets say the crook wannabe's do happen to get a seed code, All we will have to do is back up our town save on an SD card (lets pray its not like brawl, where the save cant be copied), then If we get seeded We can just reload our town before it was seeded.
Nintendo is not a bunch of idiots either, They will surely take seeding into thought when they finalize the programming stage of ACCF. So don't worry, Im almost certain seeding wont be a problem, worst case scenario, The crooktards do find a way to seed people, well just have to restart our towns, no having to go out and buy new games.