Just found this.
I've done different things in different situations, kinda like reacting based on need.
As a CP with my girls, there was little action in court. We divorced, and went back to court ONCE. The girls would ask questions when they would see their father frustrated and badmouthing me, and then I'd do my best to explain what's in the order vs. what's going on. I don't think I ever pulled out an order or a letter and let them read anything. Amazingly, they have a good relationship with their dad and myself and it's been funny to see how Dad and I will give them the same answers to questions.
As the NCP to my son, now CP, and who knows after this school year is over, I know Dad talked to our son about court, and I chose not to unless our son asked me questions. During the last round when son wanted to move and live with me, son said Dad's FIRST words were "I can't pay your mom XXX in
child support!" which of course had son crying even at age 14, on the phone saying "Mom can you come get me NOW?" I would tell son what my basic plans to get his dad to come to an agreement were to calm his fears, and then let it go. NOW Dad and Camilla printed -- yep -- printed off posts from this very site and shared them with our son and said "SEE what your mom is saying!?!?!" and I suspect that continues to this day. We're getting ready for another round and only time will tell how that plays out.
As the (former now) step-parent watching EX#3 go through his stuff, Mom (to their kids) showed the kids court orders. But she didn't show them everything, just the pieces she wanted. So with his kids, we took the approach to sit them down, HERE's the order, now you tell me where it says what your mom says it does? HAD to, to counter the attempts at alienation that were going on. EX#3 had 3 years where he didn't see his kids, and in the end, all 3 moved across country here (and yes, 1 went back because of dad's actions right after we split -- wouldn't have happened had I stayed, but I wasn't gonna put up with his crapola anymore).
So the answer IMHO is "it depends" at the same time leaning very heavily to the side of "don't let them read orders, letters, keep them out of it".
As they grow older, and become of "deciding age" the rules change a bit and the pendulum starts swinging more towards the middle.