There is also the buyer who will seize upon a missing [insert your trivial, bound for scrap box item here] and then cause more problems for you than the last dozen combined.
For as much as I dislike the weasel-wording, if you are moving dozens of kits that are unsealed, are you going to count every single part in every single box?
While we are the lunatic fringe of the hobby, as collections turn over, the folks selling them off are doing their best to get their money out and move on.
SH Tom can probably smell an incomplete kit from 20 yards away - and it is his profession to quickly review and assess the condition.
The rest of the world just ain't that good.
Assume anything that is open is missing SOMETHING unless otherwise noted.
If you're not seeing the parts you are looking for in the description, move on or bake in the "inherent trauma discount" when you buy or bid.