[greymule]

There was agreement in the other group that the actions of the runner were not interference, as his only options were to execute the slide, or give himself up.

I'd go with interference on that play. The runner has to avoid the fielder, if it means stopping or going behind.

Admittedly, this is a very rare case. I've only seen it once in my lifetime.

About 10 years ago, I had what seems to me a similar play. A runner from 2B slid into F5 as F5 was fielding a popup next to 3B, maybe 2 feet toward 2B in the base line. Just as I was calling interference, the runner shouted, "He was in the base line." So we had a rhubarb even though F5 caught the ball anyway for the third out.