[zhytkhmb] Not touch move rule

Consider a radical alternative to the touch move rule in chess: a move becomes committed only when the clock is pressed.

Before that point, a player may move (and unmove) any and all of his or her pieces.  Even more radically, opponent's pieces, too.  The only constraint is the position when the clock is pressed must be a legal move from the previous position.

Some sort of penalty for illegal move/position.  Should it be the opponent, or a constantly watching arbiter, to catch illegal moves?  The latter is possible with computers: advances in technology allow for the game to be played in different, better, ways.

Essentially a player may try playing out the consequences of a potential move on the board while it is his turn, hopefully yielding higher quality play.  You don't need to do the calculations in your head.  But the opponent can watch, too ("exposing your hand"), so it might be disadvantageous to you.

The spectators benefit by being able to see what the players are thinking.