But when it comes to coffee and amenities, they're at the ready. Here's how it works: After receiving a guest request, a human employee loads items into the robot's compartment, then inputs the guest's room number and hits the robot's "Go" button. The robots have tamper-proof lids to prevent items from being removed before they reach their destination.

On the floor of CES, LG's CLOi service robots got a lot of attention. But just across the parking lot from the Las Vegas Convention Center, two service robots--both Relay robots from San Jose-based Savioke--are quietly at work. These robots, tagged Elvis and Priscilla, are full-time employees of the Renaissance Hotel, and they aren't getting a lot of attention. When Priscilla navigated through the crowded lobby to make a delivery on Wednesday, only a few people pulled out cameras. Others casually brushed by, sometimes giving it a little pat as they passed.

Since launching it in 2015, Amazon has been improving its voice-controlled home assistant Echo, from adding thousands of recipe walkthroughs to releasing its hockey puck-sized sibling, the Dot. But soon the device will be moving in to hotel rooms, too. The Wynn Las Vegas will begin outfitting all 4,748 guest rooms with an Echo this month, allowing visitors to control environmental conditions with vocal commands. The suites will get Amazon's domestic device first, rolling out to the whole hotel by next summer. Just don't expect your room's Echo to help you plan your day, as they'll only be set to voice-control lights, room temperature, drapes and the TV to begin. Future features may include the device's fancier personal assistant features, according to the press release.