I'm not sure that would be a good idea. People may count on rtf files being readable in other applications. On Mac that seems to work, but I'm not sure it would on other platforms.
If the file format is unchanged, you can always open the document with whatever application you like, no?
I don't know on linux, but on win is like on mac, e.g. you ask to open a scr with MSWord. But at least default application is with no doubt SC.