First off, let me say it's always best to err on the side of caution with mass mailings. As others have said, when constructing an auction/sale notification list the default should be *not* adding them; only add those who respond asking to be on (...) (24 years ago, 26-Sep-00, to lugnet.general, lugnet.market.auction)
(...) I've had an auction e-mail announcement/distro/mailing list (with the default being to stay on rather than be dropped off) since 1994 and I can't remember anyone ever getting rabid about being mailed -- only polite requests to be removed from (...) (24 years ago, 26-Sep-00, to lugnet.general, lugnet.market.auction)