My wife’s cousin was a successful defense attorney in California. He could go on for hours about the easy convictions that were lost by the DAs and cops because of just plain stupidity and incompetence. Hiding evidence from the defense will get your case tossed every time.
An acquaintance got off of some VERY serious charges exactly that way. The person was a dirtbag, but the judge got incredibly pissed at the D.A.