Yes, a copyright is valid. They do this to protect their work product/intellectual property as many engineers will copy (in some cases verbatim) parts of other's reports to use in their own without permission and without citation. That's a bit of an ethical breach but I've seen it done many times.
About 3 years ago I got a call from one of my former colleagues . I had written a geotechnical report for a large project in the Bahamas. He called to ask if he could cite the report in their report. He asked for written permission. I gave it of course. He was a very senior engineer with a prominent firm in Canada, with which I was formerly associated. In my dealings with my Canadian colleagues, this approach was seemingly the norm. In the US, that is not the case, unfortunately.
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