I did not vote either way on the mirror question, but I think there is a fine line on why questions. Most people interested in travel have an interest in observing differences from place to place, culture to culture. But questions on SE are supposed to pose problems in search of a solution. Otherwise, it would not take much for the site to be burdened with trivia about practices someone somewhere finds somehow unusual.
The measure of relevance, in my opinion, should be whether a traveler would use the information to have a richer, safer, easier travel experience.
For example, visitors to London will almost certainly use the Tube. The UK being a right-hand drive country, I expected people to stand on the left on escalators in the Underground— the opposite of the US. But they stood on the right, which put me off beat for a moment, and earned me a scowl or two. I thus find
to be valuable. In contrast, I don't see any value in
I would guess the answer is a marketing agreement between Time Warner and the companies that provide hotel television systems, but that is besides the point. What is the problem being solved? How does knowing why hotel TVs are tuned to HLN improve the traveler's experience? What valuable cultural insight is gained? It's trivia, not information.
As a community-driven process, the drawing of the line will be uneven in places, because the demographics of an English-language SE site will skew differently from those of travelers in general, much less the world population. But that is why I am skeptical of such questions to begin with. The most politically and culturally neutral way to respond to why is why not? Why aren't rear view mirrors in the West aren't set down the hood to minimize the blind spots?