Recently I was doommed to coach on a 3 hour flight. I'm a big guy (6'3", 250) and was next to another large(r) than me gentleman (used loosely). He was a rather foul person, loudly cursing at the airline, and dominating the inch-wide armrest and poking me in the ribs constantly. I walked to the back of the cabin under the guise of trying to use the restroom, when in fact I was looking for 2 open seats so I could get away from this creature and not invade the personal space of another passenger.

I saw at least 5 people using the enitre middle aisle of the DC-10 to lie down and sleep. Should then then be forced to pay for 4 coach seats when they get off the plane?

I personally think airlines should ensure that first is always full. Start with revenue passengers, then go Platinum, Gold, Silver, etc. Then they should give anyone in FC the opportunity to upgrade a travelling companion.
Then they should give FC to people on bereavement fares, and full-fare coach passengers. They can keep this all hush-hush by having a standby list and upgradnig people in that priority. That way when someone was called to the podium, there would be far less of a scene than pulling them from coach.