Yea, but the driver would find them just fine if the loader followed the methods, but we don't, so we invent another method to deal with the fact that we don't follow them..
If preload followed all the methods, you'd have to hire twice as many people to get the job done. They don't follow the methods because some kid is there hollering at them to go faster, because cages are full, or packages passing them on belt.
Ups would be perfect if everyone followed the methods, I agree, but ups would not like the fallout of that because production would fall dramatically.