Using a single confirmation sequence sounds simple and attractive, but it does not work unfortunately. The reason can be seen in the Japanese 89 rules L/D example #2 (#4 is also similar but #2 is decisively wrong). The change to normal go behavior is simply too big.

In #2 the corner capture gives nonsense bonus points for the empty points in the corner (that could never remain empty in reality), while the other player may get an unfair negative bonus since he not yet surrounded the part he will capture in exchange. The outside player could throw in during main game to avoid getting robbed in scoring, but this only works in that particular example and go players will not even be aware they need to do this (since this makes no sense in real go).