What recourse do we have to help other bidders?
 

http://www.ebay.com/itm/3-CARD-AUTOG...item2a1cad29a5

Three TERRIBLE fakes and someone is buying them. you'd figure that they won't resell em, not being too "high end".

Does anyone know if we can contact winning bidders and inform them of a bad item, even if after auctions?

The only way I know of to do that would be to watch the seller's feedback to see if the buyer of the bogus item leaves a feedback comment. Then you could see their ID and message them through eBay. If they don't ever leave a comment, all you'll see is the bidders' id obscured/scrambled on the item page.

its kinda odd, because he has some other signatures that look pretty good, incl a ball w Connie Mack.

Maybe try communicating with the seller as well? It's possible that he is unaware of the forgeries mixed in his offerings. I know I sometimes make mistakes or overlook something when I'm listing large groups of items, and as a seller, I appreciate when someone points the mistake out to me (preferably politely) so that I can correct it before the error gets passed on down the line. His response to a gentle correction would probably go a long way to revealing whether he's just a little careless, or if something more sinister is afoot.

That has to be one of the worst Snider autos that I have ever seen. All you need to do is look at other ones that are being offered for sale for about 10 minutes to see how bad that is.