For nearly a year, Orbitz has been advertising “Orbitz Price Assurance” that guarantees airline ticket purchasers an automatic refund if someone else books the exact same flights on Orbitz as you did, but for less money.
Not to be outdone, Travelocity has just introduced “Travelocity PriceGuardian” which applies to airfare and hotel packages, not just to airfare as the Orbitz plan originally did. [Since Travelocity added air/hotel packages, Orbitz added hotels to its guarantee.] The Travelocity plan promises to refund the difference if another Travelocity customer books the same package at a lower price.

On the face of it, you might say what a good idea. But stop and think about it (and read the terms and conditions).
*MOUSE PRINT:
If another Travelocity.com customer books the same Flight+Hotel Vacation Package that you booked, meaning their Vacation Package contains the same flight and hotel combination (the same dates/times of travel, on the same airline/s, with the same flight numbers, for the same passenger type, itinerary, cabin, and subject to the same fare refundability, or other restrictions, and the same hotel and room type), and the price they pay is at least $10 lower than the price you booked, then Travelocity will refund the difference to you, up to a maximum of $500 per package.
What are the odds that ANYONE will book the exact same flights as you in both directions (same dates, same class) using Travelocity, and stay at the exact same hotel as you in the same priced room for the same number of nights? Slim and none.
Of course, the benefit is free, and should someone else meet these requirements and pay less (but not by using a coupon or other special offer), then you will automatically get a refund to your credit card.