I say we just mention somewhere on the server that we follow cal rules and that can solve the confusion. In cal you must be able to see the bomb when defusing (no defuse through boxes, train, tunnel) and also you are not allowed to use objects in game like debris and barrels to cover the bomb to prevent defusing. There simply isnt the room to mention every "exploit" that cal conciders illegal so let them decided what is allowed and what isnt and just follow their lead. Besides I think when a server follows cal rules and everyone knows it, it stops being a pub and turns into a warzone of people with cal experience showing off their skill.