It is not about if a hole is in play, or where your target is. It seems that it is all about "intent". You are able to putt and chip after a hole (for some reason), and flick balls back into the range, even knock a ball to your opponent with your club if he asks you to retrieve his provisional ball for him, as long as you are not attempting to play a stroke...like lining up, thinking about the swing, taking it back as you would a real full stroke. The flicking of the balls back into the range needs to be the intent of simply cleaning house (so to speek) and using a non-golf-like-stroke to do it. Like say, one handed, still walking like a polo player. Even if you have both hands on the club, your intent has to be inside you head that you are not doing this action to benifit from extra practice. Otherwise, without this rule, what is stopping anyone from taking a bag of rangeballs with them on the course, playing a few before each shot (in any direction). Then hit their real ball. It always bothered my that they let the chipping and putting go on, but I think it was to allow for mindless, time-killing, nerve-soothing, simple play with the club and ball in between hole waiting for the others to clear. And a line had to be drawn somewhere.

Now knowing this, was your intent to "practice" a few shots into that net? If so, then you lost the hole, and move to the next. If not, and you were simply not thinking about the swing in any way, just flicking balls into the net to kill time, never really taking a stance, never thinking about the swing...then you say that honestly and if there is ANY dispute, you take you lumps lose the hole and move on, otherwise if they saw how you addressed the ball in a "don't care" attitude, then you do not need to take the penalty. But always give the benifit of any doubt to your opponents in all rule disputes. State your case once, hear their case, and if they think their case is stronger, then you should conceed it and move on. This way, you are in a better position to do the same to them if they need to be penalized.