I don't think it is necessarily a respect thing, some people have different ideas of how things should be treated. I remember a guy whos speaker I was going through going mental because I had used distortion on a bass VI through his fender cab (at way below its rated level), which would apparently destroy it, because it was designed for a clean guitar sound. It wouldn't do any damage to it at all, but it was his cab, he had the right to it being treated how he wanted.
I would have no problem lending people my amp or cabs (maybe not the CTM), as they can't damage each other, but I don't think I would lend someone my bass, their idea of how it should be treated may be different from mine. I certainly wouldn't lend someone any of my main basses for some event when I wasn't in the same place watching.