OP -- I'm gonna guess you're under 30 years old, right?

Not to sound like an old-timer, but gosh, this used to be VERY commonplace on virtually all domestic carriers. Heck, I remember taking the ORD-PVD-PWM flight many a time and didn't think twice about it. Just sat on the plane with the other 60 or so pax while the PVD pax deplaned. It's just how it used to be.

Regional carriers, like Piedmont, could have flights with up to a dozen legs and stage lengths of just 15 minutes. Made for a wild day, but it was a whole lot more fun back then than it is now.