Gertie, May I take a moment and try and explain in a simpler way.
As much as it sounds like a fun idea, once upon a time (primarily pre-911) many of the finest specimens were already imported overseas, it was easy to do, and no where near as expensive as it is now.
example, look at the pictures of the snakes in say James' collection, he has fine quality snakes, available locally, inexpensively and free of hassles.
We have the same exact species available readily all over, just watch the KS classifieds, every stinking day someone grabs up a garter and asks for 20-30 bucks for it.
So the bigger picture is, the cost of exchanging snakes would far exceed the value the snakes.
And we do not wish to encourage anyone from trying to be clever, I have read stories on other forums of folks who went to reptile shows, and had the snakes seized or even destroyed on sight. (That insane fear of snakes does not exclude border patrol agents with weapons)
And I have read enough forum banter over the years to tell who is genuine and who is making things up, the one couple's story brought a tear to my eye. so really it is not worth it to try and get "snakes on a plane"
Sadly, big importers who have the money to throw around will ensure that the rain forests will continue to be plundered for a while longer, And here is a strange twist to get your mind reeling, at the same time "factory breeders" are "culling inventory"
What does all that have to do with friends trading snakes? I am just trying to explain the logistics. there are plenty of garter snakes already in Europe that need homes. It would cost a lot to do, it stands the huge risk of failure at the expense of the animals lives. yada yada yada