Scanning your Wii seems a little invasive, and I don't even really think the system is capable of doing that. I'm sure they can determine whether a code is active or not, because they can check the save file before allowing you online by requesting data from your Wii. But I doubt they can scan and find the HBC on your Wii. It just seems highly unlikely.

The only time I've ever used cheats on WiFi are through AC:CF. And I don't even play it much anymore, so I guess it doesn't really matter. I'll just stop using cheats, since I don't use them much anyways. The most I use is the ACToolKit.