worked like a charm
My outbound PDX-EWR-YUL was on CO; no upgrades, so I sat in Y. In EWR I showed the PC agent my Plat Elite card and online boarding pass (which conveniently said "INTL" across the top). First she asked if I had a club membership, but then when I mentioned the SkyTeam alliance she asked me to wait while the computer found the right program. She was able to look up the details in real-time, even reading to me that "you are allowed to bring in 1 guest." Enjoyed the EWR club near gate 100 early on a Saturday morning - free wifi and a few munchies with a fair view of the City.
My return was YUL-DTW-PDX on NW. I was EUA'd on both legs. In DTW, I presented my BP and Plat Elite card to the WC agent. She immediately said, "You're good 2 different ways: you're in F on an international flight, and you have Elite Plus status on an international flight." She obviously was very familiar with both benefits.
My experience has been that club agents often need to be reminded of the Skyteam benefit. I carry around a printout from Skyteam.com of the benefit for Elite Plus members, including one in Spanish for travel to S. Am. It has been a useful reminder for agents on more than one occasion.