I'm not a mathematician, but an electircal engineer. However, EE guys also use a lot of mathematical theory. So Mathematics Stack Exchange seems the best place to ask questions about those.
In the past months I've asked some questions about mathematical notation. E.g. Correct notation to combine functions in one function: a question on the possibility to combine function definitions in a set. So I wanted to tag the question to be related to sets. The only option for that was the tag "set-theory". The tag was removed within 2 hours.
I also asked Notation question: set of times of certain events: a question about how to formulate an equation for a paper. The questions was about sets again, but I dared not add the "set-theory" tag. So I tagged the question "notation". However, somebody removed the "notation" tag and added "real-analysis" and "functions" tag. And now I got a large answer on how to derive proof for an equation, which I cannot use in my paper.
My point being: why are people changing these tags? I know there probably are a number of math-purists here, but tags are there to attract the attention of people that might be able to help you. IMHO if somebody has tagged their questions incorrectly, then you should suggest better tags.
edit: Maybe my point/problem is: for 'newbies'/math-outsiders it's totally not clear how to a question should be tagged...