What's the real story? Were you on the right plane to begin with?

We had a recent experience where there were two flights from Detroit to Seattle leaving only 15 minutes apart from adjacent gates. For reasons I didn't exactly understand, there were a bunch of people on our flight who were actually supposed to be on the flight which left 15 minutes later. Naturally when the FAs asked those people to identify themselves, nobody spoke up. Some actually had no idea they were on the wrong plane and some just didn't want to move.

When they found the first few offenders they did physically eject them from the plane but it was taking too long, so they just finally gave up and put the overload on the later plane.

In the end it really didn't matter because both planes arrived at almost exactly the same time and shared the same baggage claim position. People were just miffed because the didn't get the seat they though they were supposed to have.

It provided fairly interesting entertainment.