I thought I would toss my hat in the "I've been in this industry for XX years"

I've never heard of a pax getting charged or fined for missing a connection or checking in and then not showing at the gate in time for departure. Happens all the time in the company I work for. HOWEVER, the airline can be fined for allowing checked baggage to go on an airplane without the pax it is registered to. This is not a 9/11 thing... although it was followed more strictly after 9/11 - instead, it came about after the Lockerbie bombing IIRC.
Also, missing your connection or flight because of something you did is a huge inconvenience to not only the airline but also the other passengers. A good percentage of all delayed departures are baggage related because some idiot left the airport between flights, or got drunk in the bar and the ramp agents had to off-load a whole cargo pit full of bags, just to find that one bag that belongs to that missing person. Something to think about when you feel like being selfish.
As for unaccompanied bags, I once had the experience of flying Toronto to LA for a trade show. I was flying standby and I didn't think i would have any trouble getting on, but a stupid doctor's convention ended that day in YYZ and I ended up getting bumped off 6 flights in a row. Finally, the gate agent took pity on me and made sure I got a seat on the last flight at 9pm. When I got to LA, I found out that my bag had shown up at 10am without me and was locked in the Air Canada claim area... with no employees in sight! They all left for the day thinking they wouldn't be needed for that last flight. Well, after staring at my bag for about 20 minutes through the window, I called Air Canada ops in Montreal and informed them that if they didn't get my bag out ASAP, I'd make a formal complaint that they violated the regs on unattended baggage. AC then called their LA agent at home and made them drive in right then to get my bag for me
