

The intent of the law was to have something to charge corporate fraudsters with if they destroyed the accounting records with proof of their fraud when served a warrant. Or illegal drug manufacturers destroying their chemlab. Ownership of the property doesn’t come into it.
The envisioned cases were always domestic crime investigations where there was already enough evidence to get a warrant. The application at customs where they don’t need a warrant is the novelty, and I really hope the government loses its case.

Not at customs. Courts have consistently held warrantless searches are a-ok before you are officially admitted entry to the country.