Hotels employ various methods to detect smoking in rooms, including: Smoke detectors: Smoke detectors are installed in hotel rooms to detect the presence of smoke. If you smoke in a hotel room and trigger the smoke detector, it will alert hotel staff. Odor detection: Hotel staff is trained to identify the smell of smoke or cannabis. If they detect a strong odor, they may investigate further. Visual inspection: Hotel staff may perform visual inspections of rooms during routine cleaning or maintenance. Signs of smoking, such as ash or cigarette butts, can indicate that smoking has occurred. Complaints from other guests: If neighboring guests complain about the smell of smoke, hotel staff may investigate the source and take appropriate action. It's important to note that smoking cannabis in hotel rooms is often prohibited, and violating this policy can result in penalties, fines, or eviction from the premises.