Question Regarding the Pokémon Anime in General

So, there are currently five regions in Pokémon:

1. Kanto
2. Johto
3. Hoenn
4. Sinnoh
5. Unova

Why, then, in Black & White Episode 2, Enter Iris and Axew, does Giovanni tell Jessie and James that they can't have their Pokémon, Seviper, Wobbuffet, and Carnivine, because it would bring in too much attention?

My friend in real life was telling me it had something to do with Unova being on a completely different continent than the other regions.

I'm still a bit confused, though.

Thoughts? Opinions?

 

That's exactly why. The other regions' Pokémon are rare in the Unova region, which is why Ash gets attention due to Pikachu (iirc). If you are bad guys wanting to go to Unova to #OccupyUnova, then you wouldn't want too much attention directed at yourself initially, would you?

 

Or: DERP, we maken you get rid of those pokemon to better advertise these new ones. Say good bye to Arbok and Weezing, the wilderness is very friendly!

>Arbok is eaten by wild Pidgeot
>Weezing explodes

That's really why they get rid of their old pokemon, aside from Pikachu, to better advertise the new ones. Of course that show stopped being good when Misty left(although I haven't payed attention since then, Misty, WHY U LEAVE TO OPERATE KH-VIDS?)
Also what Norze said, takes forever to find the older pokemon in the game, I assume it's the same in show.