Why does my NTSC-U Madworld have borders?

[Sketcz]

I'm running NTSC-U Madworld on a US Wii, through S-Video to a British, 4:3, SD CRT TV, and it has borders just like the PAL version. The safety screen for the Wiimote is fullscreen, but then the Sega logo goes all bordered, as does the rest of the game.

None of my other NTSC-U games have this problem, and the TV is quite capable of running NTSC and PAL signals just fine.

I don't get it? Surely it should be full screen?

[sj33]

Assuming it's running in 60Hz, it could just be that it has exceptionally overkill CRT overscan compensation.