Curious as to what the ~proper~ Southwest procedure would be in this scenario. (and this is not a complaint...nor am I looking for compensation)

About one hour into a recent delay, passengers were permitted to get off the airplane to use the airport bathrooms, stretch, make phone calls, etc... (the delay was expected to last at least another hour). I got off and my co-worker stayed on.

After that second hour, an announcement was made in the terminal that the flight was cancelled and that we should check in with a customer service representative about alternate arrangements. (Presumably, an announcement was made inside the plane at the same time.)

Luckily, I was 2nd in line and was able to get on the next flight. My co-worker, by the time she got off the plane and got to the front of the line, was also able to get on the next flight...but just barely.

We compared boarding passes...I was a B2x and she was a B5x. However, during OLCI the day before, she was an A3x and I was a B1x. So obviously, the rebooking process was first-come-first serve.

My question, though, is...was this the right procedure? Knowing that Southwest places importance on checking in online to get the better boarding number, shouldn't they have rebooked based on the boarding number from the original flight (ie: shouldn't my coworker have been higher on the list for the 2nd flight)?

Again, just curious.

Thanks.