Okay, this one is tricky. A player hits a practice ball back to the driving range when walking from the 2nd hole (that he has just finished) to the teeing ground of the 3rd. Is he in breach of 15-3 ("playing a wrong ball")? Is he in breach of rule 7-2 ("practice between holes")?

Here's my take on it, would love to hear your opinion:

He's not in breach of 7-2 since decision 7-2/5 mentions flicking back a DR back to the range with apparently no other intention than cleaning the course. Things may be a bit different though if the player in question takes out his lobwedge and hits the ball over the netting of the range - that really looks like "practice" to me, right?

Now, 15-3 just talks about playing a "wrong ball". Penalty: 2 strokes / loss of hole. Some of my fellow committee members say this counts as a wrong ball and thus het gets penalized for breaching 15-3, but others say it doesn't since the game is "dead" when walking from the green to the next teebox.

I agree with your take. Between holes it can't be a "wrong ball" because his ball is not in play. Hitting a ball back on to the range is not practice unless a player actually takes his stance and makes a relatively full swing. Hitting a lob wedge over the net is a full swing and thus practice.

Anyone who actually hits a range ball back on to the practice area during a competition, even if it is only "flicking" it, ought to have their head examined. Why do something that can only create a question? Sadly, there are no direct penalties for being an idiot.