Interesting specimen

[figheadair]

The sett pattern is different in the warp and weft. My guess is that it's just a fashion 'plaid' pattern.

I agree. The material is plain weave but it could still be woven that way and be a recognisable tartan however in this case it's not. The colour differences are more than just the result of it being a warp-faced (denser in the warp) cloth. The pivot stripe on the blue has an additional yellow (the pivot) in the warp. No, a Bumbee tartan IMHO.