..but, with certain types of wheels, with nearly every-revolution of the wheel, you *can* get 'hot spots' that are still quite 'coherent' - Have you ever experimented with rear-projected lumia, and seen how it can 'make' aerial-fx, in a large hazed room? It's quite cool, and I can tell ya, 'coherence' can and does still happen, nearly every revolution-cycle - yes,
divergence may be blown to heckfire, but, you can still get a reasonably-tight 'blob', or, 'fringe' that, while may be 'eye-safe',
(cause it is no-longer a collimated 'beam'..) if you've got IIIb - IV behind-it, you very-well might 'tip the Class-scale', vs the 'sticker', to the next level every so-often. It's up to each Product Manufacturer to make-sure that the product does, indeed, stay within the Class they are claiming... Not making any 'judgements' on this particular rig, jus sayin'...