Gm's should be willing to compromise as long as it doesn't go to far. Sometimes people have really outreaching ideas which are just plain not fit for a roleplay. However that being said somethings can be allowed as long as it is within the realm of what the GM originally imagined. So as a GM you should be opened minded but not to opened minded as to destroy your own roleplay. You may as well save yourself the effort of making a roleplay if one character is going to ruin it just because one person wants to be that special little different snow flake.

You should also be willing to give what you get. If everyone else is going to make a certain length CS I believe it is only fair that you should as well unless circumstances are otherwise involved.