It is okay to download a music track to try it out before buying a full price CD
There's something not quite right with the philosophy behind the question. I was reading this article about e-books via BoingBoing earlier
In the print world, the word "book" is used to refer to both the content and the medium. In the digital realm, "e-book" refers to the content only—or rather, that's the intention. Unfortunately, the conflation of these two concepts in the nomenclature of print naturally carries over to the digital terminology, much to the confusion of all.
This is not the case with music, for example, where the medium and the content are separate. The medium changes—vinyl, 8-track, cassette, CD, MP3—but music is still music. Music is the product. Music is what you're buying. The medium is just a vessel, and that vessel changes ruthlessly. When a better, cheaper, faster, or more convenient medium appears, the music follows—with or without the content owners.
I'm not downloading the track to test drive what I'd get if I bought the full price CD. The full price CD is just clutter surrounding the music. Whoever wrote the question for YouGov misses the point of music.
Ooh, that's weird, I just had this memory of helping Num Num move house a few years back and her new flatmate's CD collection, a whole wall of racks and shelves. That was a guy who liked collecting CDs. But I bet he had his whole collection on his iPod in his pocket too.