please explain "pre-moving". Anybody that hovers their hands over pieces blocking the opponent's view is low class.
Years ago, some people preferred writing down their move on the scoresheet before playing it -- to give themselves extra time to verify their move. They were allowed to move another piece and change their scoresheet.
Premoving is simply making moves while it's your opponents turn. The idea is it'll save time(bullet is mainly what it's used for). It only costs .1 second of clock time.
ok......but if you pre-move, then don't you run the risk if your opponent takes an extra fraction of a second on their move to wait for you to commit to your move -- that he/she will change their move, as they are dangling a piece mid air, to go to a much more advantageous square for their piece based on your move ?
FIDE highly recommends pre-moving in faster time control games.