Excellent, your research has reached the same conclusion as mine. 🙂  If there's been any guidance from the IRS, I haven't seen it yet.  I would just make a list of clients in this situation and blast out an email later in the year once the IRS figures out what they're doing.

Rick

PS: On one of my vacations I did some camping in the "NW Angle" of MN.  Driving there (from MN to Canada then back to MN) had the most interesting border security I've ever seen.  It was a building about the size of a small shed with a U.S. phone on one wall and a Canadian phone on the other.  You literally just "phoned in" your immigration.