Thanks! I've had a few messages (What a self-concious bunch we are!!).
Perhaps I used the wrong word - Artists, especially producers, should be able to prepare their art in any way they fancy.
Mastering, however, as well as an art is a function, so depending on other people's art, my mastering is more involved or more hands-off. This is especially pertinent when looking at a compilation which we'd all hope sounds somewhat cohesive.
NEVER apologise or try to make light of an artistic decision you've taken time to think out, be that a mix, or a sound, or whatever.