Hotel collectibles have always been popular because people travel widely and enjoy carrying away a souvenir from the place where they stayed. Surprisingly though, many people hardly notice the "do not disturb" signs when they walk past a hotel room door. They represent no material value compared to other hotel souvenirs.

Hotels use "do not disturb" or "privacy" signs to make their guests feel more comfortable and secure in places away from home. They are omnipresent on hotel door knobs in almost every nation and destination of the world. Not much is known about their origin. The first widespread use was likely in the early twentieth century in Europe and the United States, particularly by the more prestigious hotels where discretion was the better part of value. Nowadays "do not disturb" signs can be found everywhere. Guests use them to communicate their need for privacy to other guests and to the hotel staff, and sometimes take them in order to remember places of good hospitality or special moments in their lives.

"Do not disturb" signs speak a language that everyone understands. Sometimes they are eye-catchers, sometimes quite common, and their style changes frequently. Hotels often give them a customized look in accordance with their standard and the guests' need for privacy and tranquility.

Collecting "do not disturb" signs is not as simple as with other items. You can't actually buy "do not disturb" signs. They are not found in hotel souvenir shops. They are rarely seen at collectors' markets, and sometimes turn up in online auctions such as eBay. In order to acquire these signs you must actually travel and visit hotels. It also helps to have a network of friends and colleagues who travel and can get some for you. You can also exchange or trade with other collectors.

"Do not disturb" signs come in a variety of designs, shapes and materials. The most common are made of paper or card. Others are made from various materials such as plastic, wood, fabric, leather, brass, etc. Some are magnetic. Some are hand crafted pieces decorated with seashells or seeds from exotic plants. Some hotels use three dimensional objects to request privacy instead of signs.

A growing number of hotels are going hi-tech and no longer employ conventional door hanger style "do not disturb" signs. They are replacing them with electronic display lights on the hotel room door. This is disturbing news for collectors!

"Do not disturb" signs may be customized pieces designed for specific hotels or standardized signs usually found in all the hotels belonging to a chain or group. But "do not disturb" signs are not just from hotels. They are widely used in all those places where people need peace and tranquility either while traveling or when recuperating from travels. Cruise ships have them in their cabins; airline companies offer a sticker version to passengers (mostly in business class) on long haul flights.

What do the hotels think about guests who take these souvenirs? According to some, they've come to expect it and even encourage it. After all, they are inexpensive marketing and advertising tools.