I can't see a reason it wouldn't be a good idea to do so. Perhaps if it's not a valid Twitter name, it gets wrapped in slighly different code and/or CSS, to indicate it won't resolve to an actual link?

Example: http://boffosocko.com/2016/10/15/notes-from-day-2-of-dodging-the-memory-hole-saving-online-news-friday-october-14-2016/#Peter+Arnett%3A