Ooh, how about blinking text? ;)

Seriously, the bold red works best when used sparingly. For example the words "bold red" in your post stand out and grab my attention, but the sentences you wrote just sort of disappear on my screen.

How about something like:

Warning:

Your node may have some problems -

• Please limit the use of <pre> tags. When possible, use <code> tags instead.
• Please use a descriptive title (avoid 1 word titles or module names as the entire title)