Most of the vehicles I've seen used for this purpose in movies are Oldsmobiles and such from the 70s-- long before the latches were a requirement. Modern car trunks are also way smaller than older sedans, which don't lend themselves to human transport.

If you're ever in the trunk of a moving vehicle, do what you can to sabotage the brake lights-- the wires are usually accessible and it increases the chances of attracting police attention.