I always understood an open beta to be "open" to the general public. Meaning, that an application process wasn't necessary. SE really does have their own way of doing things.
Originally, "open betas" were just the beta stage when the NDA was dropped ("closed betas" still having the NDA enforced), but with the last few years of MMO releases, the idea of an open beta where anyone can jump in without an application has sprung up.
Best answer: the developer makes the rules; go with however they set it up.
"Unfortunately many game companies are learning that if they can just keep you busy, you might not realize how bored you are." - Kachi
"Pride in your character will amount to nothing more than the level of intimacy I have when I order a burger from McDonald's" - Warfox07
"I find comfort food always helps when I feel like killing myself." - Papashan (FFXIV)