As a former LA Police Officer, we would run into the "Sovereign Citizen" defense on a few occasions! Whenever these cases ended up in Calif Superior Court, the "Sovereign Citizen" lost, their car was impounded because of course, they had no need to pay registration nor have a Driver's license. But enough about that!!
If you want to read some Fun and rather old case Law involving "warrantless searches" in the INSPECTION arena...do a search on "Scope of AG inspections". It's interesting to note how some inspections(not AG specifically) are exempt from 4th Amendment requirements(building and safety for example) and what occurs when an inspector observes something out of their Scope. I only bring this up because I think we have already decided that AG inspectors are NOT Law Enforcement and as such do have certain procedures attached to following up on other "plain sight" observations and even for permissive Trunk searches.
OK...I've rambled on enough....