As someone who has talked and played with NWWC organizers and numerous EU regiments / events, the general notion is as follows:
NA is just extra trouble for EU events, and can be allowed to play but not made exception for.
As for what happened last NWWC, I have no say and was not a part of that in any way, but when I ran Team USA for NWWC we played normally and the other EU teams played us at the best time we could negotiate with them. Many competitive EU players see NA as a waste of time to try and incorporate because it often brings a baggage-load of issues, like timezones, ping, attitude to name a few.