Normally I'd agree, since that type of reverse psychology is often used in wrestling, but to be fair, Rollins himself mentioned a couple of times heading into Wrestlemania that he was prepared to cash in on the winner of the Roman Reigns/Brock Lesnar match, and we all know what happened there. It was even brought up as a discussion point here earlier this year about how it likely wouldn't happen (not successfully, anyway), since he was teasing it beforehand, but it did anyway. Of course, it's also fair to bring up that their original plans were for Roman Reigns to win the championship and that those plans were changed literally one week before Mania, but still (for all we know, Seth may have still cashed in on Reigns after he won the title.)
I don't see Sheamus cashing in successfully either way though, even though it's only a matter of time before someone does have a successful cash-in at Night Of Champions, given the PPV name and all.