How do I buy tubes?

I posted this thread, because I wanted to know what the members thought, about how to purchase tubes. Whether one should purchase, by the name printed on the tube, or by what manufacturer, actually made the tube? I know what I think, I'm interested in what, you all think.

The reason I started this thread, long ago, was I sold some tubes, that were relevant to this. They were Siemens NOS E188CC's. They were new, unused, but were labelled something else. I used pictures and descriptions, but still the buyer initiated a claim, because they were not labelled Siemens. I wanted to see if the A-gon community, felt as I did, or as he did.