Hidden tb's are the norm, especially when they hold the record id, which if it's an autonumber, the user should not see. Moving data around between forms, not so much. Not saying that's always wrong, but IMO it's often a sign that things are not designed correctly. If it has to be done then I see nothing wrong with hiding controls if it keeps the user from asking questions about things they don't need to know about.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.