How can I disable the "Text format" pull-down for users that are creating or editing content? Since the "Plain Text" format can't be deleted (within /admin/config/content/formats) the Text format pull-down will always contain it plus the default format that you would like for the user to use (i.e. Full HTML) when creating content.

When the user creates content (i.e. /node/add/article) I would like the "Text format" pull-down to be disabled so that they can't change it for non-administrators.

How can I disable the "Text format" pull-down for users that are creating or editing content?
The absolute easiest way would be to hide the selection using CSS.

I only say this because there's nothing "bad" that can happen if someone does use the plain text format.

Otherwise you're looking at assigning custom permissions and probably using hook_form_alter()  which just seems like it's more trouble than it's worth!

.filter-wrapper { display: none; }