Boy do I feel dumb. I know I've seen a key assignment for 'reset car' in the options, and I think I may have pressed it a time or two while racing and thought, "Uh, that doesn't do anything?" and forgot about it. Whenever I get unrecoverably stuck in the sand, or end up on my roof, I warp to the pits.
From reading this thread though, I think I favor the option of disabling resets - if you're in a position requiring a reset, it should be "game over man, game over." However, I also like the idea of having a reset delay; this should be significant though. A tow truck can't get to your location, hook you up, pull you out, and unhook in 10 seconds; you should have to wait a minute or more to rejoin the race.
Of course, the delay should be a configurable option as well; when I'm hotlapping online on my hidden private server, I'd rather take the easy way out. I guess I'll have to try this fancy-schmancy "reset" thingy though, if I ever wreck again (lol

)