[C210N]

These "smart" urinal cakes should be able to sense their
"ambient" alcohol level, and only perform this public service if over the legal limit. Alternatively, they could emit a "thank-you" for staying legal if under. If no alcohol detected, profusely thank the patron for being a designated driver.

[TYVets]

These "smart" urinal cakes should be able to sense their "ambient" alcohol level, and only perform this public service if over the legal limit. Alternatively, they could emit a "thank-you" for staying legal if under.

Got to wonder what it would say if I pour a little whiskey out of a half pint on it?