If nothing else, I'm sure that the scale will be plenty enough reasonable cause to search your car (whether you want him or her to or not). If they find as much as a seed, your car gets impounded and could get taken away.

I don't see how a scale could be incriminating since there are now laws prohibiting possession of scales.

But to be on the safe side, if you don't absolutely need them at the place you're going, take 'em inside.