by Hermjard
Of course: This leads to the well known notion, that a board game has no "memory" or "history". That's the reason why I assumed (3). I am not so sure with (1) and (2) though.Pro (1) and (2): The comparison between buying and exchanging, the limit of three dice, the restriction of this outdoor activity to immediately before your action (so no "history" in necessary on your side).
Contra (1) and (2): It makes no sense, why both exchange partners should be treated different. Exchanging means, you have a new own die instead of another one, no matter, if you are currently the active player or not.
p.s. Neil, thanks for your gracious legitimation of my questions. Thanks for your enlightened jugdement, what's obvious, and what's ambiguous. But it's insignificant to me.