Interesting argurment. How do you get around the warning sign, though? "You are subject to search" signs and the like tend to be upheld by SCOTUS, no?
BTW, are you a lawyer?
I am not a lawyer nor do I work in any capacity in the legal profession. My opinions are based on logic, research and being blessed with good reading comprehension.
I searched the Supreme courts rulings for every combination I could think of to find a case that dealt with implied consent searches based on signage by agents of, or in cooperation with, a Government agency. I was unable to find any such case. I did not do a search of the Circuit courts.
If you know of any such case please post as much information as you can so I can look it up.