allow periods in usernames

Scratch wrote:

allow periods in usernames

Why? What good would that bring to you? I'm sorry, but that would cause problems with comment parsing. See, if someone posted a comment that looks like this: "You should follow @chipmunkmc. Definitely trust me.", then, well, what's the username here? Is it "chipmunkmc" or "chipmunkmc."?

I honestly wouldn't mind supporting dots despite any non-technical factors, however doing so would mean changing the userregex. IMHO that would be too far of a deviation from scratch.mit.edu for this site.
Since apiclone (and potentially other software) can break upon encountering names that don't match the regex this almost feels like as significant of a change as changing the database schema or the likes.