Am only now realising that 'sewing over the pins' means exactly that - I'd always considered that it was what I did, but I have always taken the pins out just before the foot gets to them. On the very odd occasion when I have left the pin in deliberately to anchor a tricky bit and very, very slowly and carefully sewed over, I get a little wobble in the stitch line from the foot arguing with the shaft of the pin! Am actually surprised there aren't more stories of people hitting pins, it's always been a concern of mine...