Some people like to shop for cars when car dealerships are closed to avoid the salesmen. While looking at cars for sale at a closed car dealership, is it breaking and entering to open the door of an unlocked car?
Florida law states that
810.02 Burglary.— (1)(a) For offenses committed on or before July 1, 2001, “burglary” means entering or remaining in a dwelling, a structure, or a conveyance with the intent to commit an offense therein, unless the premises are at the time open to the public or the defendant is licensed or invited to enter or remain. Florida Statutes & Constitution : Online Sunshine: 810.02 Burglary
There are two relevant points here. (In this context, a "conveyance" means an automobile).
One is that Florida law states that there must be intent to commit a crime when entering a vehicle. This would be the case where someone steals parts (or the whole car) from a dealership; a crime was committed. But it would be difficult to show that people browsing through cars have intent to commit a crime, because the car dealership is in the business of selling cars, people have to get into a car to evaluate it, and during business hours, people enter the cars without salesmen.
Florida laws doesn't clearly differentiate between locked and unlocked doors when entering a conveyance or building; but obviously there would damage to a car by forcing entry by braking a window or crowbarring the door, and that is a separate crime covered under the same chapter of law.
The second point is the qualifier that "...unless the premises are at the time open to the public or the defendant is licensed or invited."
One could argue that the dealership - by not securing the car lot with a fence or signage that states "no trespassing" during certain hours - is still open to the public, even though the dealership is obviously private property. And by remaining accessible after hours, the public has been invited onto the property.
If you looked, you may see boilerplate signage at the dealership that states it is open after hours, though they are not responsible for injuries, etc.
Not necessarily "breaking and entering", and clearly not "burglary", but almost certainly trespass, unless you can prove you were "invited" to enter the vehicle.
810.08 Trespass in structure or conveyance.— (1) Whoever, without being authorized, licensed, or invited, willfully enters or remains in any structure or conveyance, or, having been authorized, licensed, or invited, is warned by the owner or lessee of the premises, or by a person authorized by the owner or lessee, to depart and refuses to do so, commits the offense of trespass in a structure or conveyance.Florida Statutes 2017