Nothing personal, but let me put it this way: As a hiring manager (which I am), if I were interviewing a potential employee and found out they didn't show up at a major airport until 27 minutes before departure, without a boarding pass and still needing to both check in and go through security, I would question their judgement, planning, and general problem-solving skills. This person seems unorganized and unprepared. Again, nothing personal.

I doubt I'd offer them the job.

I imagine the people at CO also ask themselves "What are people thinking - arrivng 27 minutes before a flight?" I can see the service reps rolling thier eyes when someone feels CO owes them something for not showing up until 27 minutes before departure time, with no boarding pass and still has to go through security.

I understand your cousin isn't an experienced flyer, but neither is my mother-in-law, and she shows up at the airport 3 hours early.

I also didn't see anything specific on CO's web site about 30 minutes, but I did see this:

The following tips will help ensure a stress-free airport experience:

Allow more than enough time to check-in and walk to the gate. Some airports may require as much as 2 1/2 hours for passenger processing. Check the website for average security processing times at major domestic airports.

Sounds like good-old common sense. CO's website shows processing at PHL is 2 hours at peak times, and this flight falls in the peak period. Real-world could certainly be less, maybe even a lot less, but between 5-6 pm it's a busy time at the security checkpoint in any major airport. But this is what is advised on Co.com and I'll bet CO will stick to that.

That being said, if you're hell-bent on finding a loophole to nail CO to the wall, good luck finding a sympatheic ear at CO. This isn't like the passenger was involuntarily bumped after being checked in and arriving at the gate per the 15 minute rule. That would be a slam dunk for compensation. I think you'll spend hours and hours on this for little or no reward. (Plus, I'd make your cousin do all this leg work. Chances are they'd learn not to cut it so close again!). Good Luck, anyway!