Not necessarily a catch, but in my case there was a business reason.

There are no BMW extended warranties offered in my country. Nada. You takes your chances. You can buy a 3rd party warranty, but not a BMW one.

But the dealers do offer CPO. I had a vehicle within the CPO eligibility range. So the dealer could get a lot more for it than private party sales prices (lots of people want a BMW extended warranty).

I called the dealer to arrange pickup of my 535. He asked if I had sold my X5 yet. When I said no, he asked if I would consider an offer from their dealership. Nothing to lose.

I would have asked $30k for my 3.0. I knew the transaction prices. I would have accepted $28,500 to $29,000. Dealer paid me $30k (his first offer, I didn't negotiate him higher) And sold it for a lot more than $30k. I also got the $4k tax benefit, by tying it to my recent purchase that I hadn't taken delivery of yet (12% plus luxury tax, on $30k). So I was $5k ahead. Win win.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue