Ok so hear me out on this one. My friend got into beta and allowed me to log into her account so I could mess around on beta. I log into my battle.net launcher for the first time since having downloaded beta. It is now patching and I can click the play button (but I haven't yet because I want it to finish). Did I get beta on my own account by accident?
Being able to download the beta is not the same as accessing the servers. If you install it and click 'play' you'll just be met with a blank server list.