Seize it all, the Fourth Amendment knows its own?

TBA tries to understand criminal procedure, but the Fifth Circuit doesn't make it easy.

Texas cops searched a man's house for explosive devices, which he possessed because he was a licensed dealer in such. The man's Section 1981 suit against the city for Fourth Amendment violations alleged that the police chief was delegated policy powers by the city and that he had a policy of violating the Fourth Amendment. The Fifth Circuit agreed the chief was a policymaker, and then stated:

Upon finding a policymaker, we must next consider whether the allegedly unconstitutional action constitutes a “custom or policy” of the municipality. We have identified two forms that “official policy” may take. First, a plaintiff may point to a policy statement formally announced by an official policymaker. See Webster, 735 F.2d at 841. In the alternative, the plaintiff may demonstrate a “persistent widespread practice of city officials or employees, which, although not authorized by officially adopted and promulgated policy, is so common and well settled as to constitute a custom that fairly represents municipal policy.” Id.

The problem with this analysis is that it seems to leave something out: an express admission of illegal policy. The court never considers, in its analysis, certain facts it had itself recited in the same opinion:

During the searches of Zarnow’s homes, police officers seized weapons, ammunition, currency, bonds, silver, band-aids, books, prescription medicines, and over-the-counter medications. Although a number of these items were not covered by the search warrant, police justified their seizure by citing to the “plain view” doctrine. Officers later testified that they understood “plain view” to permit the collection of any item that might be evidence of any crime. The police chief testified that it was his practice to seize more than was necessary during an initial search, so that he could later “rule things in or out.”

Leaving aside the egregious-seeming failure-to-train issue (the court says there's no evidence of failure to train, but I don't get how a general notion that the law says what it doesn't is not evidence of that), what about the chief's own admission that "it was his practice" to seize items not covered by a warrant?