I've never actually found this to be true. I go through Kayak, and I always check the hotel directly just to be sure. I've done this 9 times in the last 4 months for Loew's, Ramada, Best Western, and Hilton.
If you actually have a better price, then at least these brands will give you discounts or points. I don't see why they wouldn't hardcode it into their systems to not allow a cheaper priced to be reserved unless via their direct non commissionable channels, seems like a pretty easy thing to prevent.
Edit: I'm going to have to retract my comments about cheapest price being on official hotel brand websites. I did a cursory search and find many cheaper options on Hotel Tonight (and expedia) for same day reservations than the brands, and while I haven't looked at all the brand's best price guarantees, at least IHG's exempts them from having to provide the lowest price within 24 hours of checkin, so it seems like a loophole to let them dump rooms for cheaper on third party websites day of arrival.
I'm familiar with the reservations systems the hotel brands use, and I have yet to come across a situation where the same hotel room is being offered for cheaper on a third party website. It's also their official policies, and as I said, it doesn't make sense to me that they would advertise that and then not set a simple technical limitation in their reservation system to prevent anyone from being lower than them.
Yes, for some specific hotels that don't belong to a big brand, it makes sense for them to price discriminate so that the person willing to pay $500 doesn't end up paying $200, but on the level that the big brands operate, it doesn't make sense to give up 15% of gross revenue for that reason, especially when they have better ways to price discriminate by tiering their rewards members and the rate at which people earn points.
Edit: As jonknee pointed out in another post, the ihg.com price for Kimpton Monaco in Seattle is higher than the hotel tonight price, and by quite a bit, and there's a carveout in the best price guarantee for rooms reserved within 24 hours of checkin. So I guess the best price guarantees aren't really worth much...
In theory you are correct, in practice the hotel will play dumb and say they'll match it but after you file paperwork proving it was cheaper somewhere else. I've literally booked on HT from the front desk because they can't match the rate. It makes no business sense, but yet here we are.
Another example: I just checked HT for San Francisco tonight and the Hyatt Regency is up for $179 after taxes and fees. On Hyatt.com it's $259.
I see that now. I thought that the hotel would value consistently saving 15% gross revenue on commission over training people to shop for rooms on third party websites.
