The only way I could see this rule being removed is if you driving the vehicle into the ocean resulted in the vehicle being permanently destroyed, like blowing up after 5 minutes. Otherwise it would be way to easy to abuse.
Case in point: Grandma Gary is driving his HEMMT along after refining a bunch of iron (Gary doesn't believe in the illegal drug trade). He starts getting chased by 5 rebels. "Oh, I don't mind losing this iron, as long as I don't lose my $200k HEMMT, lets drive it into the ocean. It'll be back in my garage after 10 or 15 minutes," He does, gets killed by the rebels after he comes up for air. All he loses was his gear, which may have been worth only $10K and some time on making the iron, but otherwise, he comes out in front as he got to keep his truck. Rebels on the other hand get pissed because they just lost the opportunity to make some cash off the iron / chopping the truck.