That's a good idea but i think most players have their toons spread thru different accounts.
I'd suggest a system to unable trading it between chars either being logged from the same iP (that could be exploited wth account sharing), or sending them between chars logged on accounts registered on the same email address, which would be almost impossible to exploit.
The point is that yeah, the current system is quite problematic, I personally have sp & atlantis skills maxed on one char and I'm just stuck with all kind of sp containers in my inventory from tudra, nine curves, forlorn bosses and so on... Would be nice to be able to use those on my other chars without fkin up the ig market by making them tradable with no restrictions again 😛