Create own value - for registration taxonomy field

I have a registration which includes an option to select a term from a taxonomy.

The registering visitor can choose an item from the taxonomy (select box listing all terms). When I use field_permissions to assign permissions on this field, there is an option is "Create own value for field"
- does this mean that the anonymous user could add a new term? [Which I definitely do not want],
- or just that the anonymous user can choose from the existing list.
Note: If I remove the permission then the field disappears from the registration form.