Oops I did not make myself clear. When I said pallet I should have said pallet and load. Or loaded pallet. What I am talking about is very simple, you see them all the time before trucks enter yards or go under Railway bridges but extended out to all 3 sides. If the loaded pallet passes through this then it is dimensionally correct as far as height and width to go into the racking.You could easily add in the depth with an escapement mechanism. But this is old tech because you can get this done much faster with scanners these days which would also give you weight.
"95% of our issues involve the unit loads we receive from other sites"
That is a tough one because until area / National management recognizes that, it really is a game of tag. They are passing less than good product down the line, to an area that they know, they will not get serious repercussions from.
You cannot not accept them, but the good thing is you know that these are the ones to be flagged and acted upon. You can do this before introducing them into and polluting your system.
My guess is that they arrive in a bulk mode i.e. a full trailer which again makes it easier. You don't say how many are these unrelaibale pallets so I can't make a case for a sizing no/go line of conveyor with a manual size cage but that option is not expensive. It would save you a lot of heartbreak down the line. I have been in the Rack Business for over 30+ years and am adamantly opposed to anybody climbing or going into the rack. Just one slip is all it takes, and you have a head fatality. it possible you could share some of the information you are giving to the rack people for me to look at? Having been around the block a couple of times I have seen a variety of solutions in practice. Some work some don't but I live for the challenge of solving them.