Delete entries without modification

I am looking for a way to enable users to delete their own entries, without letting them modify. Here's my setup:

• I am using Formidable as a way for users to sign-up for courses.
• Each course has a separate Formidable form. When the user submits the form, he subscribes to that course.
• All users are logged into the WP site, as subscribers.
• I want users to be able to delete their entries, but not to edit them. I want a binary system: entry exists, or not.

Solution A: I tried to solve this using Formidable Views, to which I added a "delete" shortcode (without allowing front-end editing). This works fine, but only for Administrators or Editors. Maybe the Subscriber would need a specific capability to "delete one's own entries".

Solution B: I enabled the front-end editing option. Once this is enabled, the custom View works fine (the "delete" shortcode shows up for any user). But the downside is that on the actual form, when visiting an already submitted form, the user now sees both the "delete" and the "submit" button. I want to get rid of the "submit" button. I tried to edit the HTML code of the form, but would need a conditional shortcode that can tell if the form has already been submitted by the user – does it exist? Another approach would be to use CSS if the form is already submitted – but the markup seems to be exactly the same.

Any advice is welcome!