I'm generally not a fan of supporting trademarks, but with respect to USB specifically, if the product doesn't have a trademarked USB logo[1], then the default consumer assumption should be that it's dubious wank which hasn't passed independent compliance testing.
And if the product under consideration does brandish a trademarked USB logo but clearly doesn't satisfy some observable aspect of the spec, then it's liable to be a counterfeit and you should seriously be questioning the integrity of your source.