The FAQ for font licensing says that single characters or glyphs cannot be used for engravings and such. However, certain things can only be represented by a single character. This is understandable with Latin characters, where a single letter can become an almost infinite number of words or phrases, but with Chinese it is much more finite and isn't necessarily used for creating words or phrases like Latin characters are. I believe there should be an exemption of this rule for Chinese characters and similar languages that represent things with single characters, perhaps except for copyrighting logos, as it is very restrictive.