Please help answer and educate me.

I read all about the coolant-ATF mixing on the Frontiers, Pathfinders, Xtera.

Then I read one or two stories on the web about coolant and ATF mixing for the G35/37.

Is this a common issue for G35/37? As much as the Trucks? or consider "normal" that it does happen, but it's not consider an issue?

Then I read that all cars route the coolant into the AT so that could happen to any car. True?

Looking for an used car. If they replaced the coolant, there is no way I could tell, correct?