I wish it wasn't the case, but no, it doesn't take making a new arrangement for copyright to kick in.
it may be that they are claiming copyright on the compilation of all the music together, but somhow they make it so that you can't copy the music, even though it's note-for-note identical to something published 100 years ago.
Posted Aug 25, 2012 20:43 UTC (Sat) by man_ls (subscriber, #15091)
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Perhaps music publishers claim copyright on the arrangement on the page; after all music type setting is a complex task. But I am not so sure that it would hold before a judge...