The blue pentagon does not mean it's only catchable/obtainable in the Kalos region. You can have a Porygon, a Feebas, a Cyndaquil, a Tynamo, or any other non-legendary (excluding Phione) Pokémon not obtainable through regular gameplay in Pokémon X and Y (i.e. requires the use of Pokémon Bank/Poké Transporter) with a blue pentagon. How? You breed imported Pokémon, and the egg that hatches means it originated in Kalos, even though it's parent(s) didn't. That's what the blue pentagon is. It is totally unrelated to the legitimacy or availability in the wild in Kalos. Any breed able Pokémon can have the blue pentagon. I have plenty that I've bred after receiving Japanese Pokémon through Wonder Trades. They were conceived and born in the Kalos region, so they get a miniature version of the Kalos flag to prove so.
I'm aware of that, and it's not what I'm trying to get at.
What this potentially means is that people can use Pokemon that were transferred up from previous games with MT/event moves they shouldn't be able to have if they were obtained in Kalos, and use them both in the VGCs and the special rated battles, which is cheating to the fullest degree.