I drove by the corner of Rosemeade and Midway (far north Dallas) early this morning, and it was plastered with large cardboard signs attached to phone poles, traffic sign poles, etc. As I recall, the signs were for some kind of event that I think was called "Lowriders" or something like that, maybe downtown. The signs were not there last night.

I can't imagine that anyone would have targeted that particular intersection, so I'm wondering: Have those signs been plastered all over the city? If so, it would be pretty outrageous -- would there any way to get Code Enforcement to do anything about it?

It hard to say. That particular intersection is entirely in Dallas.
However, we do know there are several sharks that travel that area. It could very well be that one of them, picked up the signs.

I was by that area late yesterday afternoon and didn't see them, else I would have pulled them.
Based on your description, I've not seen others elsewhere.

GW