From the Japan Times:

Badges and mobile-phone straps engraved with the crests of crime syndicates are being offered on Yahoo Japan Corp.'s auction site. Yahoo Japan said Thursday it has yet to decide whether to ban sales of yakuza badges on the site. In June, sales of attorney's badges were banned on Yahoo Auctions Japan after the Japan Federation of Bar Associations asked the company to stop the sales.

What does this tell us? Apparently crime syndicates are official institutions, comparable with lawyer's associations.