This is the problem with grading...

[mark evans]

It seems to me that we need to distinguish between shilling where the auction house is complicit and not. As to the former, hopefully the Mastro prosecution will put the fear of God in those who would otherwise engage in the practice. [If not, and given the limited resources of law enforcement, I once suggested adoption of a hobby code of ethics to be enforced by a sort of inspector general to address shilling and other issues. This proposal was rejected as unworkable by pretty much everyone who commented. Maybe so, I don't know.]

As to shilling by a consignor or his confederates, this strikes me as more difficult to prohibit. I am inclined to agree with Peter that so long as the winning bidder pays the commission, that's the best that can be expected.