A friendly reminder to proceed with caution in Las Vegas, even though $1000 isn't even that much these days. Do Vapes Set Off Smoke Alarms? [Clear Answer] Grey Haze UK Do Hotels Know If You Vape? What Happens If They Find Out? UponArriving Will Vaping Set Off Hotel Smoke Alarms? Your guests aren't the only ones checking in. So are their vape pens. With over 13 million regular vapers in the U.S. alone, unauthorized vaping is a major operational risk for hotels.