I've never had an issue, of course I'm not talking about $50,000 cars. The last time I did it was a couple of years ago for $7500 for my son's truck. A few other times as well (also for ATV's and the like) however it was always under $10k, so maybe that had something to do with it. YMMV of course.
I remember my old Man getting an Amex card in the mail back in the 80's and the included benefits brochure suggested he could charge a car to his card and I immediately thought how BOSS that would be... still doing it whenever I can at 51. 
