I've swapped front/rear before, if the tire going up front is good enough. Or perhaps wanting to push a tire to the back to grind it down some before the rubber dries out and it goes bad.

Flats happen and are part of riding.

Blowouts are rare. I've had two in the last couple of years. One was on trailer wheels made with kid's bike tires of unknown age, perhaps rusted wire beads, and too high of pressure.

the other blowout was on a tire, 75 miles from new. No obvious cause, other than perhaps inflating it cold, then riding it hot. It happened to be on the rear, but it could just have likely happened on the front (new tire).