Guests at five star hotels, in the likes of Beijing and Shanghai, popular with foreign business travellers, reported that they could login to previously blocked websites while connected to lobby WiFi.
The South China Morning Post broke the story in an online report, which was deleted just hours later.
One visitor to Beijing, who wished to remain anonymous, said that he used his mobile phone and laptop to access both Facebook and Twitter in the lobby of the St. Regis Beijing Hotel and in his hotel room during his stay.
The guest said: "It's not just St. Regis. A lot of my friends told me that they can also access Facebook and Twitter in many other five-star hotels in Beijing.
"This has even become an unspoken secret among many local Beijingners. If you want to get on Facebook and Twitter to post messages, especially to your friends who live abroad and use the two social media sites often, now you know where you should go in Beijing - go to those five-star hotels."
Even five-star hotels in smaller cities, such as Dongguan, an economic boomtown in the Guangdong province near Hong Kong, offer free WiFi to visitors, allowing them to visit Facebook and Twitter.
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