I keep telling people--it's a sport, not a genuine policy. You just have to read this forum to see that.
If booking channel A has a promotion (e.g. 20% off stay longer, 3 nights for 2 etc etc) on the exact same room category, same view, same date, same bed type, same cancellation condition, and it‘s cheaper than Hilton.com (no promotional offer), I guess the promotion in itself already got disqualified from price match?
Certain kinds of "promotions" are exempted in Hilton's T&C. For instance, the "member rates" at Priceline and Expedia. You don't have to be signed in to get them; they look like regular rates. But they don't count. But if the "promotion" is just a lower rate and everything else is identical, then go for it. But don't get invested in the results. If you don't like playing the game, don't indulge in it.