2.) How do they ID the person? For example, say Joe Bloggs uses web check-in. Gets itinerary and boarding pass. Mr Terrorist wants to use Joe Bloggs' boarding pass to get on the plane. How do they authenticate the identity of the person travelling as opposed to the person who 'checked-in'? Does someone check ID at the airport before they get on the plane??
This really isn't any different to you checking in at the check-in counters and then giving your boarding pass to your friend Mr Terrorist at the boarding gate.
The most "secure" method would be checking ID against boarding passes as they step on-board the plane.