I can't understand why a switch would be configured to Fail Open? Surely an attacker could easily exploit this by MAC Flooding which will cause the switch to act like a hub and broadcast messages to all network interfaces?
The only reason I can think of is to prevent any critical systems to fail from loss of communication if a switch was configured to Fail Safe?
I would appreciate your thoughts on which contexts would it ever be appropriate for switches to be configured to Fail Open?