Are online travel sites arbitraging away gains from hotel price discrimination?

I glean from this Marketplace story that this may be the case. Hotels tend to charge many different rates for the same room to take advantage of huge variation in the demand elasticity across different groups of consumers. Moreover, you can book a room directly with a big chain hotel or you can book the same room through arrangements they make with online travel sites. But by outsourcing the booking to an online travel site, the hotel loses some of its ability to charge different prices. It would be poor public relations to come out and say, "these guys keep us from charging high prices to some of our preferred customers." But these quotes suggest that the online sites are allowing inelastic customers to get prices aimed at more elastic customers.

“They've just shifted business that might have come in direct to the hotel or to some other channel,” she [Estes Green from Kalibri Labs] said."

...

Hilton’s chief marketing officer, Geraldine Calpin, said skirting commissions to travel sites “was not the intent of the strategy,” which she said was more focused on better anticipating and serving guests’ needs. That's easier to do when they book directly through Hilton. 

“If you're booking through a third-party site we know less about you,” she said. 

Usually, a price discriminator must vertically integrate into the low-priced, elastic portion of the market to prevent arbitrage. Instead, hotels tend to serve the more loyal, high-priced, inelastic portion through their own website. It will be interesting to see how this is resolved.