Do you understand the dynamic?
He rolled up and put it in park and rolled his window down an inch or so
He deflected the LEOs questions with a question
He did not reply to the question about having a drink.
a) it was a leading question with a potential follow up:
'Sir, if you haven't been having anything tonight do you mind if I ask you to blow into this device'
If you refuse you can take the ride.
If you answer anything the stop is now consensual.
He waited until the right time (a supervisor, since only she can release him)
The supervisor continually scanned his face for alcohol use, eyes, bloodshot, etc. (being a professional)
After she couldn't reply in the negative to his final question, "Am I free to go?" he was able to drive off.
This may not be the outcome of a stop in your state, so do know your laws.
IMO, this puts anyone at risk for illegal search. As we know people searching have planted evidence (it's possible, though improbable). You do not allow a search for this reason alone. But, who knows you may have a spent casing under the mat due to it being in your cuffs when you left the range.
Anyway, that's my 'way too deep' analysis, lol.