There's a new hack going around where people can log into your account using a thing called a "usb gecko" and all they need is your
profile's secret "login ID" to do it; which they can grab using your leaderboard rank. They can sign into your account using this exploit and can basically gain full control of it.
Pardon my french, but this hacking bullshit is getting ridiculous, why isn't the Wii team doing anything to rectify this?
EDIT: Hopping got worse now. They don't even need a gecko device anymore. The scumbags came up with a new hack called a "Proposal hopper". What they do is send the victim an ally reuqest and then they can gain control of your account that way. Here're more info:
The only way to counter it is to deny ally requests quickly. Also, if you have homebrew on your Wii, there's a new hack out that blocks the proposal hack. I'm not gonna post any links due to fear of being banned, but you'll find it if you search Google. These are only temporary fixes though. The anti hop hack only works when you're signed in, and the gecko hopper hack can't be stopped by anything. The only way to permanently stop account hopping is via a patch.