Hide Line items if user is logged in
So I've done something similar (I used the group a user was a part of vs just a user) with a template 'extra' file that contained javescript and a quick call to the API. Not sure if this is the ideal method but it worked to show/hide some content.

https://civicrm.org/blog/dave-greenberg/now-its-easier-add-custom-behaviors-templates

Javascript Contact API - how do I &#39;do something&#39; with results