Well, for one thing, Laquer on cars is ACRYLIC laquer,, it is a different base carrier than Butyrate Dope. Both laquers, but completely different chemistry. ( One of the reasons I harp about using the thinner designed for your paint, not some other stuff) The other thing is, consider the guy behind the counter, if he sees the delamination 5 or 10% of the time, he is NOT going to want to reccomend it because of his reputation. The biggest factor i think is that our creations dont spend 24/7 in the sun AND probably more important, on a car the solvents have nowhere to go except into the urethane clear. Whereas on our planes, the solvents can go AWAY from the urethane through the covering and wood to escape. Keep in mind, laquer NEVER EVER dries completely, it is always out gassing solvents so when you top coat it with Urethane those solvents have to escape somewhere. On a car, they cant go Down, theres metal there, so they come out of the laquer and break down the mechanical bonce between the laquer and clear causing delamination
Hope this helps...
Still , do I think its a good idea,, in the purest sense, simple answer, NOPE. will it work,, most times yes assuming you allow the laquer enough time to truly dry