I have worked for companies that dealt with content filters. This was in the UK where a number of counties in the south of England have “sex” as the last three letters. The problem is non-trivial.

And if you think it is, my second sentence here contains ‘have “sex”’ in a context that is very hard to distinguish from a context a school might not want their students investigating. If you are reading this through your school’s blocker… well you might not be. It might have been blocked already.