I tried to drag the brakes to engage the pistons lightly over a long distance and the behavior did not change. Sticky calipers should lead to the car wander and not track straight since there's deviations in wheel speed. If it's in the front, you would also feel it in the steering wheel. I'm going to borrow a friends' pyrometer to check the brake disk temps and look for deviations as a sticky caliper would also lead to a rotor exhibiting a higher temp.I initially thought the same but so much is “lost in translation” when folks are describing what “they feel”. Sticking Caliper piston could and does translate to a shudder or vibration feeling. PTV and sticky caliper piston are two totally different concepts/conditions.
RE: PTV, the point I'm trying to make with that example is when the brakes are engaged for an individual wheel, the deviation in wheel speed will prevent the car from tracking straight and begin to pull to a side.