yo, yeah man, that shit does work, i got stopped driving in the uk, but i already had been sucking a 2pence piece for 30 mins or so, and i passed.
I had about 5 or 6 pints and drove home about an hour after, so i would defin be over the limit, but the 2 p does something special and makes you pass.
i think there are certain boundaries though, like you cant have 15 pints then exspect it to work.
Also it makes you pass but its not recomended, remember you are still pissed up, its dangerous, the 2 p is a prevention againt the breathliser, the 2 p will not make you sober up.