I've been told every package that get unloaded in most hubs gets reweighed/measured while getting unloaded.
I've given quite a few of these packages back.
If proper weight on them, and the taped sides are the same size, then all is good.
We had a customer who would ship empty PO priority boxes, and claim things that obviously couldn't fit in it, and file claims on them. LP canceled several of their accounts, but they kept moving, and opening new accounts.