Wiki text that is preformatted (bracketed with triple curly braces) is not visually distinguishable from normal text (at least not for my eyes). I usually prefer to have such text, which usually represents code fragments for command line input, visually differentiated form the surrounding text.

I have a patch that adds a 'wikipre' class attribute to the PRE tag, and adds formatting in the wikiStyle.css file. If you are interested, I can open a JIRA and attach the patch.