You realise that every single thing reviewed in a paper magazine is a loaner review unit, unless it's Consumer Reports, Which?, or one of about three others? It's an industry standard.
Sure, but the authors of larger magazines typically do not get to keep (or even use) the product for their own private purposes, so they're not nearly as invested and have far less reason to be biased.
I've heard many companies "forget" to ask for their seeded samples back, particularly those sent to so-called influencers.