Seized calipers feel very, very, very different than working brakes. In fact, if confronted with that situation, I'd almost want proof. Seized open, then the brakes don't work - nail the brake, and the nose will dive... and the whole thing will take much longer with much more effort than if the system worked completely. Seized closed, then the brakes drag, which makes a lot of noise in some cases, but basically would feel like something threw an anchor on in the trunk. Modern, maintained disc brake systems should not seize without abuse or some other signs before the "surprise" note at the dealer.

The problem is that you've taken the brakes apart already, so the proof is gone.

 

Both of my rear calipers have seized before, scorching my rear pads. If you drive this car in the winter and park with your handbrakes on, they will seize eventually. The fronts should not seize though.