What are the stats on the percentage of drivers stopped for DUI that are actually over the limit? How low can the percentage get before it becomes prima facie evidence that the cop's judgment of "probable cause" is unreliable?
Your concern is warranted (no pun intended).
But again, there will be so many people truly DUI this weekend & tonight the cops won't need to mess with the marginal cases. It becomes an even bigger waste of their time, resources & credibility than necessary. Why go through all that then have the perp/accused go free because your evidence wasn't strong enough?
Especially with so many sh*t-faced people on the roads this weekend?