Sorry it took me so long to reply. As you know, we tried this before. While this is a good way to reduce some of the unused vehicles on the server, unfortunately it caused other problems as well. Getting the word out is not easy. A lot of players new to the server, which would be the bulk of the offenders, are confused when they log in and their vehicle with all they own in it are missing. Many leave and never return. Many players figure it was too much hassle or the price was too high and just abandoned their vehicles and started again. Then there were the trolls that just couldn't resist destroying so many vehicles so close together and getting off on the chain reaction explosions.
One big problem was, since it was impossible to predict when a vehicle owner would log in, the lot would have to be tended pretty much 24/7 and nobody was willing to do that and it fell to the admins. In the end, it turned out to be simpler for the admins to move the vehicles from the trader left for more than a reset or two, or delete them after a while. If you are willing to devote the effort to manning the lot, then I guess we can give it another try, but be aware that tending the lot can get pretty old after a week or two it seems.