Very odd customer service at this location. Kitchen staff on point and fast. Stayed at Rio a few days and this is a great location for a Smashburger that should be operating better. I'm a Smash regular at various locations and I have no idea what's going on with this place. At no point would they open up more than one register to take orders. Tonight we tried again (Friday night at 7:30). 20+ people in line to order. One person at the register. We bailed on the line when we realized it was almost hopeless to wait through it all. We went to the outskirts of the restaurant regroup and noticed what appeared to be a manager just standing at the back watching from a distance, and then retreating further away and not diving in to help, manage, guide, or anything. Then he continued to look at his phone and turn his back on all of it while overlooking the casino floor down below. Not sure why they have 4 registers if they are only going to operate one. The food is fine at this location once you can actually place and order and get it in hand.