[greymule]

Talk about a HTBT play!

I'd most likely go with the "weak" interference and send the runner back to 1B. Had a similar play a few years ago:

Abel on 1B, Baker hit a soft liner that F6 jumped up and speared. Abel had started for 2B and tried to scramble back to 1B. F6, seemingly still in the air, threw off balance to double up Abel, but his throw was not strong. Abel slid safe into 1B, and his momentum carried him up into F3, who was bending over a bit to field the now-rolling ball. To soften the collision, Abel reached out and briefly put his hands on F3's arms. F3 tried to move to his left to stop the ball, but in the tangle, he fell and the ball rolled out of play.

I gave Abel 3B, but reversed myself after thinking about it and sent Abel back to 1B.

It seemed to be enough interference to prevent Abel from getting 3B, but not enough to warrant his being called out. It seemed to me that he had done everything legally and then simply instinctively tried to protect both himself and F3.