Should mathematical symbols and equations be included in a word count?
To me, the key question is this: what is the purpose of the word count?

If the purpose is to fill in a blank that says: "word count goes here", then just take the simplest approach that will give you a number and don't sweat the details.  Personally, I would run "wc" on my LaTeX source in such a case.

On the other hand, in some cases word count is being used to determine how the length of your document relates to a minimum or maximum length.  If it's actually strict, then they'll generally provide clear guidance; if it's an approximate guideline (which is usually the case), then again, just take a reasonable approach that will let you conform and don't sweat the details.