agree with you CC, now that you mention it. so what about if both those squares are removed? the red and gold background should be fine no?
Using red, gold or either of those blues is probably best avoided, as it refers to the flags of Spain and/or Catalunya.
Luckily the weed scene has largely avoided the petty nastiness of the independence politics, plenty of people are friends with Catalans and Spaniards, groups, coops, clubs, many span the divide and politics is kept out of it, thank ****
I would strongly suggest that the artists concentrate on something Barcelona specific, the skyline, sagrada familiar or gaudi/mosaic/guell imagery is all perfect and will not provoke any shitstorms.