I've only sent cards to SGC, back when a rejected card that you didn't have slabbed as "A" came with an explanation.
had one come back min size, Short top to bottom, but factory or they'd have written trimmed. (also had one come back "trimmed all four sides... obviously didn't look too closely at that one before sending it)
This one has very rough cuts top and bottom, not trimming, but not typical, so rejected.
This one has weird cuts, caused by debris in the stack of sheets being cut, or on the sacrificial strip in the cutter.
I really doubt anyone would give it a number.
Consider also that despite being "experts" they won't grade
Sets that are difficult - Star basketball, Fro-Joy Ruth...
Cards that aren't in a published guide. (when there sort of isn't a guide anymore... )
Pretty much anything they think is "too difficult"
It's all about appearances, and limiting the chances of them looking foolish even if they're right.