We don't know that this was a "welcome here come inside our secure zone". It is entirely possible that Rick has them living in another portion of the prison at least for awhile. This keeps them secure while keeping them seperated.
"Sometimes the point of doing something is not to find the "best" way of doing it, but to discover the most fun" - Gever Tulley
"Use peaceful means where they are appropriate; but where they are not appropriate, do not hesitate to resort to more forceful" Thupten Gyatso (the Dalai Lama, 1932)
"It is not the will to win that matters - everyone has that. It's the will to prepare to win that matters" Coach Paul 'Bear' Bryant.
"The ink of scholars is more precious than the blood of martyrs" - Muhammed