In the US, it used to be not a foul to knock object balls onto the floor. If you had scored on the shot, you continued at the table. It was also the rule at 3-cushion billiards. Balls driven off the table would spot. There were carom fancy shots where a kiss could be avoided by flying the first object ball into the lap of an innocent spectator.nope, perfectly not legal. that's why you have to spot/owe a ball after doing so
As I recall, this changed about 1980, plus or minus a decade.