Case-law generally dictates the conditions under which a police officer can search. The cops can search any car on public property without a warrant. It's gone all the way to the supreme court.
...and it's being abused. It was never meant to be SOP, which it has become.
It's so easy to lay the blame at the feet of those who pass the laws: legislators and judges, isn't it.
Absolution is yours, therein.