Nor do restaurants give RN credit for all credit cards - even if they accept them for purchase!
Yesterday, I had lunch in a joint that I recalled being Visa/MC only. My bill folder contained an AMEX promotional blurb (there was no AMEX logo among the door stickers), so I asked the waitress, who said that they accepted AMEX as payment. I checked later, and AMEX is not shown as RN-eligible; I'd used my MC debit card, thinking this was one of those "just because you can pay with the card, doesn't mean it's a 'valid' transaction" episodes.