I was thinking that the sticking throttle was MOT failure, but wasn't sure on that one, so kept schtumm...
But it does raise an interesting point - if your bike fails its MOT, its classed as not road worthy - so if you fit one of these devices, which when deployed creates a situation akin to a MOT failure point, is your bike then not roadworthy? And if that's the case, your insurance would be justified in refusing a claim should you have a crash?