You still slow down. I knew several people that ran these on their Audis.
You need to run it in combination with a V1. You leave it on, cruise at speed. Once the V1 lights up (indicating you are being tagged) you slow down to the speed limit or just above and flip it off. If you are quick, you have no issues. If you take too long, you get to enjoy an imprudent speed ticket. Cops use laser guns every day, they can tell when you are jamming the signal, and will be far more pissed than when you aren’t. If you think you are going to cruise by cops with it on you are sorely mistaken.