I'm not denying the point of the game, I'm saying that a moment of not following it causing massive punishment is not very fun.
Imagine if Dark Souls was roguelike game. With no practice for the bosses you'd hardly ever progress. "GIT GUD" shouldn't apply to roguelike games, as there is little to no time for you to practice the unexpected one thing that you were expected to know before apparently.
There are going to be a lot of people coming from the game jam either not knowing how chess works, or not having paid enough attention to it to know about discovered mate. The frustration received from being punished for a game mechanic they did not know about is understandable, and should be prevented in some way.
And there already is a way to prevent it - the shields. If you make some stupid move by say, not seeing a piece all from across the board, not realizing you are being attacked, or just misclicking, the game will highlight the attacking pieces and spend a shield, instead of saying "GIT GUD" and ending your run. So a harder to notice possible attack should suddenly do otherwise? Just doesn't make much sense to me.