[greymule]

Thanks, and what rule do I use to back that up?

I don't think it's in the ASA book in black and white. I asked that question a few years ago at clinic, and that's the answer I got (send the following runner back).

You might make a case for "two runners cannot occupy a base," but I think that's weak.

I did have that play happen, though. Two runners on 2B, and the pitcher ready to pitch. Needless to say, you won't see this at higher levels.