Possibly you should get a more up-to-date reference. Just because there is no definitive rule for the use of hyphens, that does not mean they should not be used. They exist to avoid ambiguity; they make reading a sentence such as the one above a lot easier. They are a courtesy extended to the reader by the writer. This is why robyn referred to "attributive" hyphens, rather than "correct hyphenation" or simply "hyphens".

Ref: Eats, Shoots and Leaves by Lynn Truss.

The pink-tutued good fairy has spoken.

"That also might be close to the best-ever selective quoting."

thanks I wondered if any one would notice rather than just argue the point.

But I'll remeber for my next Uni Essay...

// a ground breaking cassette only label

Ground-breaking and cassette-only aren't compound words. They're being used as adjectives to describe the label.

But you (and Fowlers) are right in that when it comes to hyphenating compound words, the rules are, there are no rules.

At work we consult the Oxford English Dictionary to see what they say, but there is a complete lack of consistency. It's just how the English language has evolved in a sort of organic way.

But attributive hyphens are generally consistent with their use and are bloody useful. It's the difference between a used-car salesman (he will sell you a used car), and a used car salesman (he was used).