I don't think the rules as given are viable. Stalemate is defined as a condition where you don't have legal moves, but are not in check. Making a move illegal that cause stalemate thus makes a recursive definition, where it is not clear that the recursion will always terminate.
They also do not address the 50-move problem. What if a game ends in K+R vs K+R? There exists over 10 million positions with this material, so it would be really tedious to force a repeat. But since there is no way to force checkmate, you would eventually be forced to repeat. Which is illegal. But you might not be in check. which makes it a stalemate. Which makes the previous move illegal. But other moves there might (directly or indirectly) suffer from the same problem, so now that position would be a stalemate too. Etc.
I suppose that eventually one of the players would be forced to sacrifice its Rook as the only legal option, but it seems pretty much undeterminable which player that would be. That applies to every position that under normal rules would be a dead draw, e.g. K+B+N vs K+B+N.
I don't think the rules as given are viable. Stalemate is defined as a condition where you don't have legal moves, but are not in check. Making a move illegal that cause stalemate thus makes a recursive definition, where it is not clear that the recursion will always terminate.
They also do not address the 50-move problem. What if a game ends in K+R vs K+R? There exists over 10 million positions with this material, so it would be really tedious to force a repeat. But since there is no way to force checkmate, you would eventually be forced to repeat. Which is illegal. But you might not be in check. which makes it a stalemate. Which makes the previous move illegal. But other moves there might (directly or indirectly) suffer from the same problem, so now that position would be a stalemate too. Etc.
I suppose that eventually one of the players would be forced to sacrifice its Rook as the only legal option, but it seems pretty much undeterminable which player that would be. That applies to every position that under normal rules would be a dead draw, e.g. K+B+N vs K+B+N.