Hmm...this got me thinking. My glove box lock is broken (common problem in the 850), so it can't be opened. I have literally no idea what's inside.
Using a block heater is like giving +rep to your car.
You also CAN refuse a search of your vehicle without a warrant but that never ends well and isn't exactly recommended.
The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.
I'm absolutely certain the one thing you can't find there are gloves.