I read all these replies before posting, ignoring the restrictions on applying rebates, etc. for me the greatest disincentive is the bank issuing the card itself.
HSBC SUCKS.
My brother in law is a die-hard Pontiac fan, his father worked at the Edison plant till retirement, so they get the GM Family bonus, plus whatever GM Card bonuses. Sounds good, right ? Twice in the last year or so, when they have had problems with a vendor and called for customer support, they had to jump through endless hoops, spoke with several (ahem) "offshore" people, and in the one case were refused a chargeback on a faulty purchase, absorbing a >$100 loss. The one dispute that was successful required faxing the same
paper form multiple times because it kept getting "lost" and literally dozens of phone calls. They would not even process the dispute until the form came in.
A little bit of googling, and you will find that HSBC customers are Number One (i.e Worst) in Identity Fraud.
EDIT: http://repositories.cdlib.org/bclt/lts/44/
On the other hand, I have had a few chargebacks in my time, I call Citibank, speak to someone who responds in English, and presto, the dispute and temporary credit is done. Once I document the issue, I have never failed to get a complete refund.
And I get 2% back, on any make of car, new or used.