Hmmmm interesting.
Our crew had this three weeks ago and I talked them out of OPI (I had no doubts).
So when I saw this thread I pulled up the book on Arbiter and saw this ruling and was a little surprised and sent an e-mail to my crew saying I owed them a root beer. Sending a new e-mail this morning... glad I don't owe.
Thanks for pointing me in the right direction.