There must be a mechanism to stop windborne pollen or seeds leaving the facility. This can be done by (a) building the facility so it contains pollen or seeds, or (b) enclosing whole plants or their inflorescences so pollen and seed cannot get out, or both. The note gives growth cabinets, selfing bags or other devices that keep pollen and seed release to a minimum as suitable mechanisms.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.