I've been doing a fair amount of reading/research here the last couple days. I'm beginning to feel that yes, the runner may return, and in the OP, the runner can retouch and be protected. That said, I also feel that had the runner immediatly attempted to return, he would keep the timing play alive and no run would score. The difference being, he crosses the plate, stops, sees the out on the BR, comes back and touches, instead of missing the plate, immediatly returns and just misses touching before the out at 2B.
That sound about fair to most?
