This rule was imposed upon us by our FAA cabin inspector. She is assigned to Alaska Airlines by the FAA the interpret the CFR's as they apply to Alaska Airlines. You can choose to blame who you want, but our FAA cabin inspector is the one that interprets the CFR's, not the Alaska Airlines folks. As far as this rule applying to all airlines - that's not so. For instance, Southwest F/A's are able to stand outside of the aircraft while boarding or deplaning is going on. We, at Alaska, must be fully inside the airplane during the entire boarding and deplaning process. Another rule, as interpreted by our FAA cabin inspector. Alaska did not make that rule up.