Hi! For the most part, visitation is only approved for contract purposes when a character (Dominant or Submissive) is jailed for failure to contract. If a Dominant is in jail for any other reason, their visitors would be much more limited—generally only their Submissives and/or any business associates (co-owners or managers of a business they own) would be allowed to see them. Visits take place in a small meeting room set aside for that purpose. They would be able to visit for a maximum of one hour per day, one visitor at a time, supervised by guards. Visitors will be searched on entry and aren't allowed to pass any items to the person in jail.

The power nullification field covers the whole jail, so yes it would extend to visitors as well.