Just to stir the controversy… Should we categorize sour blends from U.S. (or anywhere) as gueuze? Unless we have full on agreed to respect the notion that lambic by definition must come from pajottenland.
No matter what the answer is i dont know why some brewer in north america hasnt made a living mixing classic allagash/ jolly pumpkin or whatever sours and selling them.
If something is spontaneously fermented I use the lambic styles. It does seem a fairly complex subject that is not dealt with all that consistently though. Do spontaneous ferments using barrel microbes rather than leaving open count? How important is the wheat aspect? There are certainly barrel aged blended fruit sours made here which I have left as sour / wild ale even though they’re made a lot closer to the traditional method than some of the Belgian fruit ‘lambics’.