Currently, users who are blocked from editing a wiki are prevented from publishing into that wiki using CX. However, this means that they may have unpublished drafts which they may not be able to access if Special:CX is not available for them. This will create loss of work and may also prevent other users from translating the same article (separately).
Users may be blocked from editing one wiki and not another. In such a case, they need to be warned at the start if they are attempting to translate an article on a wiki where they are blocked, while not preventing them from accessing Special:CX entirely.