Maybe the scent of weed isn't enough to justify a vehicle search, but if a cloud pours out the windows like you've just finished a road trip with Cheech & Chong, that may be a different story.
Sure, that air-freshening pine tree or scent bottle might help take out the lingering odors of your trip through the Taco Bell drive-thru, but that doesn't change one big drawback: it's illegal in Illinois.