I can only assume hotel prices will also begin to inflate.

All the areas Amazon is going to occupy are in the Arlington County and JBG Smith plans to develop anyway. Amazon is essentially going to fill the role vacated by DoD after BRAC as the dominant entity in the area.

If they need more hotels they'll build more hotels. It's a pretty expensive area anyway. Hotel rates will probably stay lower than downtown DC and comparable to Tysons.

...CC will get it (and somewhere in/on Long Island too). Really thought it was going over to the Dulles area.  
It's going to make a lot of things in the Crystal City neighborhood interesting and not just hotel prices.

rent is higher. Traffic would be insane as well.