Do cops have to tell me why they're searching my car?

A slight hijack: Has there been a case in which someone successfully made a defense against a claim of probable cause due to the fact that the officer (say, repeatedly) asked for his consent to search?

ie “If he was so sure I had drugs, why did he ask me five times if he could look in the trunk?”

[QUOTE=Uncommon Sense]
So, again…if they’re looking for a weapon, can they open up the 35mm film cannister on the floor of the car.

[QUOTE]

Those bullets have to be hidden somewhere.

Supposing I’m pulled over at 2 in the morning, just after the closing time of local bars, and I’ve not violated any laws that I’m aware of, which is to say that I have not had alcohol, do not have a firearm or drugs, have obeyed the speed limit, have working seatbelts, lights and turn signals, which were all used. In other words, I’m pulled over for what I would deem to be harassment, in my non-expert opinion…

I refuse to consent to a search, politely but clearly. The cop becomes annoyed, decides to make my life miserable by holding me for three hours and writing seven tickets, as described by Hal Briston. Seven tickets? What on earth could I be written up for, especially given that the officer hasn’t searched my vehicle?

In a worst-case scenario, of course.