[feanaro]

Your text says it's not. What's legally important is to make certain parts of the text conspicuous.

Using all-caps is one way of achieving this, but there are other options, such as using a different typeface, font size or colour.

[Ensorceled]

How do you use a different typeface in a plain text file?

[rdpintqogeogsaa]

Disclaimer: I am not a lawyer. The following is not legal advice and, in particular, has not been tested in court to the best of my knowledge.

You can't use a different typeface, font size or color in a plain text document. That does not mean you have no options. The criterion is that it is “written, displayed, or presented that a reasonable person [...] ought to have noticed it.”

Consider the following:

    Nihil  harum  autem  impedit  commodi  ut  occaecati.   Nihil
    quisquam ab molestiae veritatis consectetur.  Quis  molestias
    sunt  facere  tempore  est.  Eum quia quisquam veritatis illo
    minus sint atque ipsa.  Omnis optio ducimus  minus  nemo  non
    deleniti  voluptas.   Blanditiis  nisi  eum  eum beatae fugit
    delectus.  Optio neque sed nostrum veniam eos.  Culpa ut  no‐
    bis  rem  est dignissimos est eum sed.  Occaecati dignissimos
    eveniet odit aut est ipsum minus nisi.
    
    
    
    
                           !! IMPORTANT !!                 
                       DISCLAIMER OF WARRANTY              
                                   
        The software is provided "as is", without warran‐
        ty of any kind, express or implied, including but
        not limited to the warranties of merchantability,
        fitness for a particular purpose and noninfringe‐
        ment.  In no event shall the authors or copyright
        holders be liable for any claim, damages or other
        liability, whether in an action of contract, tort
        or  otherwise, arising from, out of or in connec‐
        tion with the software or the use or other  deal‐
        ings in the software.
    
                                                                      
    
    
    Unde sint ab qui ut.  Debitis qui deserunt fugiat aut nihil
    impedit vel saepe.  Et ad voluptas quia.  Omnis libero  ni‐
    hil  perferendis  aut  ab.  Illo et neque voluptatibus.  Et
    animi consequatur enim eius aut at veritatis.  Modi error a
    ratione  tempore  velit inventore.  Accusantium accusantium
    et quam quis nemo id.

This seems rather noticeable to me, gets to the point, and is considerably more readable.

By using the all-caps sparingly, we've made way to draw attention to the heading, then offset the passage with large amounts of whitespace to draw attention to the passage itself. At the same time, this keeps readability of the actual text that you want people to read.

[numpad0]

BUT ALL - CAPS TEXT IS EASIEST AND AT LEAST TO ME SOUND RIGHTEOUS ENOUGH. I THINK THIS IS A CLASSIC CASE OF QUOTE IT AIN'T STUPID IF IT WORKS END QUOTE.