I recently had the chance to shoot some stills and time-lapse from the City Center in Las Vegas.
To make shooting through the double glass windows easier we used Lenskirts.
The LENSKIRT is a portable, flexible hood which you attach to the end of your camera lens. It allows you to shoot pictures / video through glass without internal environmental reflections such as yourself, room lights, camera flashes, light leak from under a door.
The resulting view was great. The above shot was a 3-second exposure and there's no reflection.