With airlines changing the rules of their frequent-flier programs to help improve their balance sheets, it was only a matter of time before hotel chains began to re-evaluate their own loyalty schemes.

Still, many travelers were surprised, confused and even angry when, earlier this month, Hilton Hotels Corp. announced two major changes to its program, Hilton HHonors. It made it more difficult to qualify for elite status, and it restricted access to so-called executive lounges at its high-end properties. In 2005, Hilton pioneered a “rolling VIP tier qualification” system, which replaced the industry standard of requiring a certain number of stays or nights during a calendar year — from Jan. 1 through Dec. 31 — to win elite status…