I (captain) always clip in. My stoker was reluctant, but our bike mechanic suggested it was a safety thing since on flat pedals if we hit a bump her feet could come off the pedals. That could be inconvenient, or it could be injurious. We got some "learner" Shimano clip-in pedals (Click'r). The release tension is very low. She is very happy with them. She has no problem unclipping, but more than once has remarked after going over a bump that without them she would have lost contact with the pedals.