This isn’t quite as bad as it seems at first, and I’m someone who sees overreaching by police (civil forfeiture and war on drugs among others) as one of the biggest issues facing the US.

Yes, the initial stop was improper, but cops have always been able to make up some BS about not signalling while changing lanes or similar excuse to pull you over.

The key is that the driver agreed to a search, then wanted the results of the search thrown out because the initial stop was technically improper. NEVER agree to a search. Make the police get a warrant. Had the driver not agreed to a search, this would have gone the other way.