Just let them pass it.

They'd HAVE to draw blood to test this.

Cops would be required to be licensed phlebotomists to draw blood, and I can guarantee you that this would be a huge civil rights suit.

This 'solution' of theirs is nothing more than a HUGE malpractice/civil lawsuit waiting to happen, plus an even larger drain on their resources.

This will likely pass but never be enforced once the true cost is known to the department.