Although Hong Kong is a special administrative region in China, it has some characteristics, including its
border with Shenzhen, that give it the flavor of an independent country. One way Hong Kong is country-like is that it has its own country code for international phone calls. Not only are the country codes different for Hong Kong and mainland China, but the rates for calling the two regions can differ as well. On a billboard in Phnom Penh, Cambodia, I saw one example of how this can present a challenge:
I can't say with certainty why the sign is in English, but it is worth pointing out that it was located in the midst of areas where many foreigners can be found. And not only does Phnom Penh have a number of expats living there who may want to frequently make international calls, but in Cambodia it can be much cheaper for foreign visitors to buy a temporary SIM card than to use international roaming on their regular number. In fact, the company advertising on the billboard, Cellcard, had been recommended to me for this purpose.
Whatever the case, it is factually incorrect for the sign to describe Hong Kong as a country. But since only listing China would not indicate the rate to Hong Kong, it makes sense in this case to mention both Hong Kong and China. It's possible the sign's creators were unaware that Hong Kong is not a country. However, it's also possible they appreciated Hong Kong's status but decided that the concise statement "6 cents to 11 countries" was still preferable to any alternatives they considered. Sometimes simplicity trumps accuracy.
Instead of addressing what Hongkongers may have to say after seeing this sign, I'll answer another question that may now be on some readers' minds. Along with Austria, Australia, Brunei, India, Germany, Indonesia, Pakistan, Russia, Sweden, and the UK, at the moment the
cost for calling Taiwan is 15 cents per minute. I didn't see any signs for that though.