You can use HTML, so you can manually add an <a> tag. If you use the squiffy-link CSS class, it will be styled the same as section and passage links.
To add a link that does nothing when clicked - just use onclick="return false". You can add a tooltip by setting the title attribute in the HTML tag.
This example brings all of the above together:
This is a genuine [link], and this is a <a href="#"
class="squiffy-link" onclick="return false"
title="This is a tooltip">fake link</a>.
[link]:
You clicked the genuine link.
You can run this example here: http://docs.textadventures.co.uk/squiffy/scratchpad/?gistid=d2da6df246f60c7f9d4f&filename=links.squiffy