WOOT! Found what I was looking for.
http://tipmra.com/kgb/WEB/general/ProLaser%20III_om.pdf
On page 22 there is a description of the HUD aiming check:
A stop sign is just over 30" across, which means the beam could be 15" off from the aiming reticle when centered on a stop sign. Using the calc
here, this translates into an aiming error of +/-.716 degrees. My speed was measured at 430', at which distance the reticle could be off by +/-5.37 feet!! Add to this the fact that the beam width at 430' is almost 12", and the beam could be as much as 6' from where the reticle is centered.
I know that I've indicated the worst-case scenario, but given the fact that I was on a motorcycle with a front fairing width of 26" and travelling approximately 36" from the faster vehicle, I have quite a bit of wiggle room.
So, I'll start off with challenging the hearsay of the certification and if that fails try the "He didn't target me, he targeted the other guy" defense. Only, I think the numbers back up that defense nicely.