Originally Posted by BWISkyGuy

IME it's definitely not new, it just varies a lot by merchant, which may be why you haven't run into that yet. I'm very averse to having miles clawed back so I haven't pushed this at all, but I have lots of friends who are a lot bolder than I am and are willing to push their luck and think the reward is worth the risk... They've shared a couple of pitfalls here for the past couple of years. One is tracking on the merchant's side so they know commissionable/non-commissionable promo codes right up front, and another are accounting systems that tie commissions to orders so they can at least report on dupe commissions paid (to different channels), enabling clawbacks when the cost of the dupe commissions exceeds a certain amount.

I think this thread shows that enough merchants either don't enforce the rules in many cases, or only enforce them over a certain threshold because the juice isn't worth the squeeze, but I think if you scroll back long enough you'll see plenty of reports of merchants with these checks/tools in place.