imho, for some folks their playing technique is the expression of their style, resulting in their guitar's 'mojo'
(& job security for their guitar techs/luthiers 
)
I have to agree with you . How do you have such ready access to these links to help make your point? ... awesome. I was thinking of Willie's guitar when I was reading your post. Nevertheless, I ordered a static cling pick guard from Taylor to have on hand ... just in case... I have no problem with someone carving a new hole in their guitar if in the process you are putting out awesome (ooh , twice in one post) music, but that's not me.
Changing direction a little ... which I can do because I started the post, right? ... Another example of one of of two extremely talented musicians who has worn an extra sound hole in his mandolin in a very short period of time is Brian from
Switchback(
http://www.waygoodmusic.com/)... if you ever hear of them coming to your area , buy tickets and go see them!!!.... especially if you can see them in a small venue.... no , wherever they are playing, go see them. I think Brian told me his mandolin is three years old and he has worn another sound hole into it.
PS , I have no affiliation with Marty and Brian = Switchback other than being a huge fan. For the last severall years , they have come to our little Illinois town ( pop= 1100) to play for small, but very appreciative crowds.
