Kind of reminds a story I was told by a USGS photographer. He took some film into a place in Tucson(very well known and I use them myself) He handed his box of 4x5 color negs he took on a once in a lifetime survey of the Grand canyon after the controlled flood, over to the guy and they were filling out the order form. And it was super busy with a small staff. The guy behind the counter asked him how many sheets. The photog did not remember so being the smart ass he is said "better open it and count them." Without thinking the guy did, in the bright sun lit lobby.