Lawyers and judges have spent a lot of time with this. Agree or disagree about their conclusions but questions like those tend to get answered (and INAL but I've read a little) by adding follow up questions to get at the truth. i.e. Did they say a specific time? was there a plausible manner? Was the place specified? You can probably imagine other things to add to that.

We all know that famous "I know it when I see it definition" but I think that's an exception rather then a rule. A lot of those things really can be given a reasonably clear definition.