This was not made clear. While it may be practical in some cases, I don't think, in the general case, that restoring positions in pool is either realistic or desirable. It's feasible in snooker because the kind of foul where the "shoot again" option is exercised is usually a softly hit kick in which few, if any balls, are moved. Fouls in pool happen on all kinds of shots and at all cue ball speeds and restoring the position of the balls can be near impossible in far too many cases for this idea to work.