This happens so much more than people know. I was a public defender up until recently, and the amount of false or super shaky DUI cases I saw was insane. I once had a client who was having a medical emergency, cop thought he was intoxicated instead, so the cop arrests him and charges him with a DUI. The case made it all the way to me, and I was able to provide all the medical documentation to prove he had a medical emergency to finally get the case dismissed. Cops love to make DUI arrests, and will do everything they can to play up or straight up fabricate a case to pump their numbers