IIRC, I think there’s a comment about this in the Official FAQ, in the answer to playing two fields at once on the same device, I think.
The way I’m remembering (not a quote) is Sammy said that playing two fields at the same time on the same device isn’t a good idea. (It seems that the fields clash when played on the same device at the same time.) He goes on to say (at least in my memory) that you can play your two fields at the same time on two different devices. But he didn’t make the typical distinction of “one physical, one environmental.” I don’t know if that was an oversight or if that’s no longer an issue.