A method of selectively forming a barrier between adjacent seating regions at which first and second support surfaces are respectively located, with the first and second support surfaces configured to support first and second persons in laterally spaced sitting positions. The method includes the steps of: obtaining a barrier assembly having at least one wall structure that is configured to be selectively changed between: a) a storage state; and b) an operative state; and changing the barrier assembly from the storage state into the operative state wherein an exposed surface of the at least one wall structure is situated to obstruct lateral movement of at least one of: a) an arm; b) a leg; c) a head; or d) a torso of a person in the sitting position in the first region into the second seating region.