I get the need to turn off "Allow Rez" for the mainland public areas.
To prevent griefing and such.
But it would be safe to say that if you're a premium member, you would be less likely to commit a grievance since you're paying for your account and getting banned from it is an incentive for good behaviour.
As such, allowing premium members to rez on "Public Linden Areas" (with an auto return 5mins) would make life easier for those of us who enjoy traveling on the roads or seas with vehicles. Especially if we hit one of those dreaded banlines/zero second security orbs returning our vehicles and forcing us to spend the next few minutes trying to find a tiny square to rez a new vehicle.