Because the Gideons put them there!
The Gideon Bible is not some special version or translation of the Bible that hotels really like (the books are usually plain old King James Versions); they're named for the group that distributes them.
Gideons International got its start in 1898, when two traveling businessmen, John H. Nicholson and Samuel E. Hill, arrived at the crowded Central Hotel in Boscobel, Wisconsin, for the night.
The two had never met, but there was only one double room left, so they decided to share it. The men got to talking and found they shared a common faith and had both toyed with the idea of creating an evangelical association for Christian businessmen.
They decided to give it a shot together. They called a meeting the following year for men who were interested in joining together for “mutual recognition, personal evangelism, and united service for the Lord.” Only one other person showed up to that meeting—William J. Knights, who suggested they name their organization after Gideon, an Old Testament judge who led a small band of men to defeat a much larger army.
As the group expanded in its first few years, most of the new members were men who frequently traveled for work and spent many of their nights in hotel rooms. They wondered how they might be more effective witnesses for Christ on the road, and hit upon the idea of providing Bibles to hotels. They could be used not only by the Gideons’ members as they traveled around the country, but also borrowed by other guests in need of them. They started with the Superior Hotel in Superior, Montana, then set out to put a Bible in every hotel room in America. Since 1908, they’ve distributed more than 1.7 billion Bibles, expanding beyond the U.S. to more than 190 other countries.
Passing Them Out
The Gideons don’t go room to room themselves, slipping the books in nightstands like Bible elves. When a hotel opens, local Gideons members will present a Bible to the hotel's general manager in a small ceremony and then give enough books for each room and some extras to the housekeeping staff for distribution. In addition to hotel rooms, the Gideons also give Bibles to military bases, hospitals, nursing homes, prisons and to students on college campuses.
Each Bible handed out is free of charge, and the project is funded entirely by donations to the group. The Gideons will also replace any books that go missing or get worn out, and the group says that the books have a six-year life expectancy, on average. They don’t get bent out of shape when people ignore the “thou shalt not steal” rule when it comes to the Bibles, either. They’d rather you just take the book if you need it that badly.
Based on the success of the Gideons’ Bible project -- the group’s own statistics claim 25% of the people who check into a hotel room will read the Bible placed there -- other religious groups have begun distributing their own free literature to hotels. The Marriott hotel chain, founded by a Mormon, places the The Book of Mormon in many of its rooms, and many hotels also offer Buddhist, Hindu, Christian Scientist or Scientologist books along with the standard Gideon Bible.