https://www.theregister.co.uk/2019/08/05/black_hat_defcon_hotels/

Black Hat If you're heading off the Black Hat and DEF CON security conferences in Las Vegas, USA, this week, be prepared to have your hotel room searched if - for any reason - you shoo maid service away and stop staff from cleaning your room.

Most hotels in the city enforce mandatory checks within their rooms following the October 1, 2017 mass shooting from the Mandalay Bay hotel, now the home of the Black Hat conference. A murderer, whose name isn't worth recording, killed 58 people and wounded 422 after hauling an arsenal of weapons into his hotel room, and raining bullets on a music festival crowd below.