I disagree because an artificially seasoned disc is one that would normally be seasoned through normal play, not a post-production modification like adding paint to disc to make it heavier. The only difference is that the "seasoning" is done intentionally with quicker results.
Whatever normal objects that people experience on a course that seasons their disc are acceptable objects to use to artificially season a disc. So, trees, concrete (walls, pavement,etc), rocks, etc. can be used to artificially season a disc.
Also, in regards to the rest of the context of the rule, the rule sounds like it is referring post-production modifications and not seasoning, whether artificial or not.
My argument was that intentionally seasoning a disc was something that did alter a disc that doesn't happen during normal use and by rule is technically illegal. I didn't say that I agree with the rule nor did I say that I don't have a wall and gravel parking lot that I use to knock the new off of discs. I said that "by the letter" it is disallowed.