One of the baddest experiences during training is with the smith, and not only ounce, but three times.
One time doing press, the shitty system makes to rotate the damn barbell to lift it out, and put it back. During last rep on hand slipped away during the rotation. It was just above my chest, but damn, 280 lbs dropping for two inches does hurt.
The other time was with the smithsquat, or so its been called. Small injury in lower back.
Last time was with neckpress, or so it's called.
If you're used to free weights, dont make the change to smith. It will hurt you cause the motion is unnatural.