Tierno and Cheren in the same deck but not Juniper and Sycamore??

[JohnnyBlaze]

How can I explain to new players at my League and tournaments the reasoning behind both Tierno and Cheren which functionally do the same exact thing and both of those can be run in the same deck versus the Juniper and Sycamore ruling that those two cards cannot be run in the same deck but also functionally do the same thing. It comes up every week and I cant offer a reasonable explanation. Seems a bit illogical doesnt it?

 

[PokePop]

We don't give advice or speculate on the reasoning behind Pokemon rulings.
All we can do is say what is allowed or what is not allowed.
We can explain card interactions, but OP decisions are beyond our knowledge.