Well, more of a trap than the actual game, really. That's saying a lot, since the protagonist of Cross Days (from 0verflow, developers of School Days and Summer Days) is a male cross-dresser who gets himself into situations on both sides of the swinging arc, if you know what I mean.

No, this trap is more meta, and potentially more dangerous. Apparently a trojan/virus has been released alongside copies of Cross Days flowing through the Japanese P2P networks, disguised as a fake installer. When activated, the program gathers data from the computer and pretends to take a survey of players, including asking for personal information. Once it's done, everything gets uploaded to a public website, alongside a screenshot of their desktop.

Once discovered, users can ask for their data to be deleted, but must first click a button acknowledging that they have illegally downloaded Cross Days. Better yet, the whole scheme is revealed in the fake installer's terms of service agreement, something no one reads.

It seems that public shaming is now a weapon being wielded in the war against warez, though obviously the implications for identity theft and blackmail mark this particular stunt as somewhat dangerous in its own right. You can visit this page for some detail on the virus, as well as collected screenshots of the offending players' desktops. View for yourself the daily activities of day traders, otaku, readers of ero fanfiction and normal people who tried to score themselves Cross Days for free.

Truly though, the real lesson of this escapade is to be very careful about what programs you try to open when picking up your software from shady places. 

[Thanks to Ko for the tip!]