I'll bet you didn't know it was a serious crime to have your tape recorder on during a DUI traffic stop:
Dover Man Charged With Taping His DWI Arrest
Rochester, NH. May 9 – A 48-year-old Dover (New Hampshire) man has been charged with tape recording his own drunken driving arrest in Rochester early today.
Police say they saw Christopher Power sitting behind the wheel of a vehicle with its motor running just before three o'clock this morning.
After speaking with Power, police charged him with drunken driving, and discovered a running audio recorder on the driver's seat. In addition to drunken driving, Power was charged with wiretapping.
I can see where cops wouldn't want any evidence of what really happens during a DUI "investigation". Ask any LAPD cop.