Ever wonder what that $30-a-night “resort fee” on your recent hotel bill was actually paying for? Depending on the property, it could have covered anything from Wi-Fi and “complimentary” bottled water in your room to gym and business center access—which you may not have even used during your stay. Either way, you were going to end up paying for it, no matter how enticingly low that advertised rate was. This practice of tacking on additional (and sometimes mandatory) fees to basic rates is known as “drip pricing,” and is most commonly encountered in resort destinations such as Hawaii and Vegas.

But the days of hotel-bill sticker shock may be numbered: late last year, the Federal Trade Commission warned major hotel chains that they’re required to include any mandatory fees in their advertised rates—rather than tuck them away in the fine print at the time of booking. According to a letter the FTC sent to 22 hotel operators in November: "While a hotel reservation site may break down the components of the reservation estimate (e.g., room rate, estimated taxes, and any mandatory, unavoidable fees), the most prominent figure for consumers should be the total inclusive estimate."

This development could be great for travelers, but we have yet to see it become a reality. A recent rate search on Vegas hotel sites, including the Venetian and the Palms, revealed that daily resort fees are still getting footnote treatment; our check of the online travel agents showed the same (Travelocity and Expedia declined to comment on whether they had plans to comply). The dream scenario? An industry-wide enforcement, similar to what happened last year when the Department of Transportation stepped in to compel airlines to disclose mandatory taxes and fees in their advertised rates. But until this happens, buyers beware: look before you leap at that too-good-to-be-true room rate.

Jennifer Flowers is an Associate Editor at Travel + Leisure and part of the Trip Doctor news team. Find her on Twitter at @JennFlowers.