A well-known scammer on Mercenaries (MouS), who stole around 700euros and has been permanently banned on the mod for years, was among the first ones to get access to the Bannelord beta thanks to his team (Unity) getting invited to the beta alongside FT and AE.
If that's not telling of how little control there is from Taleworlds on who get access in the beta, I don't know what is. If you are smart enough and get to reach a developper through TW or Discord, you can easily bullshit them, pretend to be someone you are not and get a key for not only yourself, but your friends aswell. It already happened and will likely continue to happen because some of them are simply lost af, completly disconnected from the community and won't bother checking the most blatant lie thrown at them.
On the other hand, they might just arbitrarily refuse to grant you access to the beta if you end-up asking the wrong person.