Still doesn't make sense to me, or else everyone who happens to share a dreamworld with us and is out there somewhere would stumble across themselves in film trailers too. That seems dangerous.
Anyway, Ultron's not my expertise and I haven't a clue what the hell that is, but I'm more interested in the possibility of regular citizens stumbling upon their own film trailers. That suggests this dream bullshit might not just be contained to Orange County.