Many profiles now contain comments from the artists themselves!
As a visitor to their site you must abide by their terms as stated in each artists profile. 
Should an artist require email approval first you must contact them directly.

    •ALL USAGE OF ARTWORKS ON THIS SITE ARE FOR NON PROFIT RECREATIONAL
USE ONLY•

Here is the link to the site that contains a complete list of all the Artists that allow..

"Free to Use Tubes"plus"Downloads"
of most of their Tubes.