Police decide who ingested exactly which drugs based on a 12-step collection of clues gathered by staring into suspects’ eyes, pinching their muscles, taking their blood pressure and watching closely how they walk and talk and balance.
Where I live, you can refuse a breathalyzer, but then you’re taken to a blood test. If you were just on the edge on the limit, it might be worth it, because it takes a while to go to the blood tests so unless you’ve just had a drink, you’ll have time to metabolise a bit.
Except if you refuse a breathalyzer, you are presumed guilty, not innocent.
Where I live, you can refuse a breathalyzer, but then you’re taken to a blood test. If you were just on the edge on the limit, it might be worth it, because it takes a while to go to the blood tests so unless you’ve just had a drink, you’ll have time to metabolise a bit.