Actually, you get a "Finished pit-stop" message. And the "pitlane in" "pitlane out" messages are there too. What I mean with the in out variables would be the actual pitboxes because you could be stationary in the pitlane (and be detected as being in there) but it won't be necessarily at the proper location to start the pit-stop process.
However you are right, the "reward" wouldn't really be that great if it's used for implementing pit-stop sound-effects.