I think manufacturers have to agree to certain things like long term (almost open ended) loans to reviewers, no preview of review, keeping some distance after item has been set up and verified to be working properly, etc. I knew a speaker manufacturer about 15+ years ago who refused to do these things (he really wanted to stay in touch with the magazine on a regular basis and know what the reviewer was thinking all along). He got only one review, which was positive, but ended up pissing off the mags with what they claimed was his "butting in" too much.
