Pedro Martínez: as I understand they have agreed to resign the game. Best would be if the bug would be fixed ofcourse, or if we could at least get back to the previous move so the game could go one.

Chaos: Well, people who have accounts and play at BK are deemed to have agreed to the User Agreement and to the rules of all games that are played here. My understanding is that when my opponent (or anyone else on this site) makes an illegal move (i.e. a move which is not in agreement with the rules applicable to BK games), I am fully entitled to require the management to have such a move reversed. Therefore, I think the list of “obligated players” is rather redundant since they are obligated to that effect (not to make illegal moves) already.

Pedro Martínez:
As I understand it, a player may inadvertently make an illegal move due to the bug that would otherwise be impossible. More critically, in certain positions with few remaining movable pieces, a player may be forced to make the illegal move which would otherwise be prevented without the bug.
In either case, a player may have a legitimate argument that the illegal move was unintentional. With the list, voluntary resignation is agreed upon without involving a moderator or management and no move reversal is necessary.

Have such moves been reversed?
How long does it take?
What happens if unidentified pieces become identified as a result of the illegal move?

Dark Prince, Chaos:

Have such moves been reversed?
Yes, they have.

How long does it take?
It depends on the method of reporting the illegal move. It takes Fencer much less time (and effort) if reported to him directly via PM than if reported in the BugTracker (or at least this is what my experience tells me).

What happens if unidentified pieces become identified as a result of the illegal move?
I have no idea. Good question though. :)

Pedro Martínez:
If reported to Fencer by Private Message, would it take hours, days or weeks to reverse an illegal move?
Would I be correct in assuming it would still be reversed even if several moves had been made since it was reported? The potential problem with previously unidentied pieces would apply here too.

Dark Prince: Unless Fencer is on a vacation or something, the reversal will definitely not take longer than a few days.
I believe your assumption would be correct indeed. The problem with undesired identification of pieces would have to be taken as an inevitable side effect though.

Pedro Martínez:
YEAH...
That's enough for me, however unlikely it may be, to go with the list and agreement by opponents to resign in case an illegal move is made.

refers to identification by SPY, but also indirect identification.
i.e. a "1" runs up on a bomb and explodes identifies that piece as a bomb narrowing the choices to attack to destroy the BASE.

Pedro Martínez: Is it at all possible to have the move reversed? At BK some things seem to be impossible while they seem logical and wanted, like the next round of a tournament starting as soon as the winners of the previous round are known. In that case we have to wait untill all games of the previous round have finished, whether or not their outcome is relevant. That's why I wonder if it's possible to have a move reversed. My guess is it can't.