One thing that's never really touched on in all the restoration debates is the "ethics" of certain procedures. Does it bother anyone else that something like an arrival date is removed for purely financial reasons (e.g., to make the book more saleable?)
In my view, an arrival date (or even the original owner's name) is part of the history and charm of a book, and something is taken away from the book when the arrival date is removed. There is no legitimate "conservation" reason to remove penciled writing -- it will never harm the book.
To draw a comparison, in autograph collecting, it is unethical to "wash" the personalization off of a signed photo. (A photo that is signed, but not personalized to a recipient, is typically worth more on the secondary market... so some dealers have been known to remove the personalization "To Joe Blow" leaving only the autographed signature.) Of course, it would be unethical to alter a historical document to make it more appealing for sale.
It really makes me wonder how much the big-shot dealers and collectors really love comics. If they truly loved the history of the books -- and just weren't obsessed with having the best copy to inflate their egos -- they wouldn't tolerate needless cosmetic alteration of these treasures.