​This summer's travel bummer: No free hotel Wi-Fi

As travelers hit the road this summer, some might be in for a rude surprise when they check into their hotels: no free Wi-Fi.

Wi-Fi has become one of those staples, like clean linens and spotless bathrooms, that travelers simply expect when from a hotel, but that's not always the case. Ironically, the more expensive a hotel is, the less likely it may be to offer free Wi-Fi, which may be because the management feels its better-heeled clientele can afford to pay up for Internet connectivity.

Yet that might be a short-sighted approach to hostelry, based on a May survey from online booking service Hotels.com. The site found complementary Wi-Fi is what more travelers look for than any other feature when booking a leisure stay. Six out of 10 respondents said they wish free Wi-Fi would become standard at all hotels in 2015.

"We know that free Wi-Fi has been the most sought-after amenity since we began doing our annual amenities survey in 2012," Taylor Cole, a travel expert for Hotels.com, wrote in an email to CBS MoneyWatch. "While the demand for free Wi-Fi remains, it appears that it's starting to become more of an expected offering than a differentiating benefit."

Given that so many travelers are focused on free Wi-Fi, why isn't the hotel industry adapting? One reason is that it has lost revenue from two long-time moneymakers: the hotel phone and on-demand movies. As travelers increasingly arrive with smartphones and laptops, they can bypass making expensive calls via the hotel phones or watching movies on their room's TV set.

That's prompting hotels to turn to other sources of additional revenue, such as charging for Wi-Fi.

Not surprisingly, some battles have ensued, especially over one workaround that hotel guests have used for sidestepping Wi-Fi charges: the Wi-Fi hotspot. In one instance, Hotel giant Marriott International (MAR) was accused by the Federal Communications Commission of blocking customers from using their personal Wi-Fi hotspots and then charging them as much as $1,000 per device to use the hotel's network. Marriott settled the charge for $600,000 last year.

Other hotel guests skip checking their email in their rooms and head for cafes or restaurants such as Starbucks (SBUX) to use free Wi-Fi in those locations.

One tip for travelers: Ask if joining the hotel's loyalty program will give you access to free Wi-Fi in the chain's locations. Many bigger companies are rolling out such programs, including Marriott. Other hotels that offer free Wi-Fi in exchange for enrolling in a loyalty program include InterContinental (IHG), Starwood (HOT) and Hilton Hotels (HLT).

Of course, it's not only free Wi-Fi that matters, but the speed of the connection. According to a global survey from the site HotelWifiTest, many of the best chains for both speed and free Wi-Fi tend to be those located outside the U.S., with Nordic Choice Hotels -- a chain that owns hotels in Scandinavia -- ranked No. 1.

The top-ranked U.S. chain is Marriott, although HotelWifiTest noted that "the results are not all that impressive compared with the top hotel chains from the global chart." Only 17 percent of Marriott locations in the U.S. offer free Wi-Fi, the study found.

Still, Hotels.com's Cole noted: "The industry as a whole is definitely taking notice and making strides toward making Wi-Fi a complimentary offering."