I wasn't meaning it to be literally how we would pronounce fu, with a strong f. It's more of a half way between an H and an F, like an extremely soft F really. One could make the argument "people will say it wrong if they use a hard F like we normally do" but let's be honest, they're likely saying the -ton (pronounce "toe-n") as ton, as in the measurement (pronounced "tun"). So we more likely have a bunch of people going "ca-tun", "ray-tun" (some may realize it's rai as in right, some), "hew-tun" (or, god forbid, "huh-tun"), etc. I don't think punctual pronunciation should be a primary concern more than practicality based on the Hepburn Romaji system that's been more accurate for years now than the others.

Also, I hope that's not the case with the couch thing. I would hope they wouldn't care about if people were stupid enough to confuse a ninja technique with a piece of furniture.