So I looked at the Medarda Map again of Piltover's Trade Route .....Piltover trades with Ionia
For Hextech? I know there is numerous locations that also have what they are offering for trade. But looking at the top right corner( http://na.leagueoflegends.com/en/featured/piltover/medarda-heirloom ) You can see Ionia's location and have 3 things written: Raikkon, Pallas(Varus's home) and Kashuri.
I remember a rioter saying that Ionia is very interested in Piltover a while back(sorry i can't provide the link.) But it just hit me that Ionia now makes hextech in their own way and could potentially be trading Piltover for hextech resources. Especially when there are some in Ionia that want's to get back at Noxus.
I find this theory very Interesting. So, did some one in Zaun refuse an offer from Ionia, only for the cabal to send Jhin and make an example out of them?