The user only knows about swiping-to-delete primarily through:
- Discovery by accident or experimentation
- Discvery by transferred interface expectations
- Signifier: a graphic sub-element that tells user that the element can be swiped
- Tutorial, whether in-app or by another person
You are deciding between:
- Visible and disabled
- Invisible and disabled
Where (in)ability is determined by user authority.
Is authority easily obtainable? For examples: getting X points, verifying email, or having a Y-day old account. Whether authority is easily obtainable or not determines whether the ability to delete an entry falls or doesn't fall within the user's area of concern. If a user cannot be expected to obtain sufficient authority—say because entry deletion meant to be solely in the few administrators' domain and never in the many users'—then it's none of the user's concern: there's no point in dangling something the user will never have. If this is the case, make the ability invisible and disabled so users don't need to know and probably won't ever need to know.
If the user can expect to obtain sufficient authority, and thus entry deletion is in the user's area of concern, then knowledge about entry deletion ability is relevant. That brings us back to the first list about how the user can know about swiping-to-delete.
If you make the ability invisible and disabled, it is incompatible with having a signifier because the signifier would signify nothing, a frustrating experience for a user who would assume that the signifier is misplaced. It is inconvenient with discovery by any means because if a new user, in building their conceptual model of their new app's interface, tries swiping a list element and gets no feedback, then they'll assume the element doesn't afford swiping and then move on. When the entry deletion is finally exposed, then you will rectify the user's conceptual model of the interface with a tutorial.
If you make the ability visible and disabled, then when the user discovers through any mean that a list element affords swiping, the user will also discover its intended, albeit not yet exposed, function, and the user will appropriately incorporate that discovery into their conceptual model. Signifiers will be compatible because the swipe affordance they promise will be delivered. Tutorials will be redundant.