I can't speak to Alexa's ultimate range (sorry, I couldn't resist that), but it obviously depends on conditions. I've been very impressed with her ability to work with colds, "frog" in throat, and such. I'm not sure how she reacts to drunks -- that would be FINS area of expertise. As far as 15,000 sq ft coverage is concerned, you can use multiple units and multiple Dots would be cheaper than a gaggle of walkie talkies. In theory multiple Alexa's can triangulate your position in a room.