Introducing guest access for Office 365 Groups!

From the blog post: "Guest access works for any email accounts including corporate and consumer domains (such as Outlook.com or Gmail.com). If the guest email identity is associated with a Microsoft account (such as Office 365 or Outlook.com accounts, for instance), the user is directed to a sign-in page to identify themselves. If the guest doesn’t have a Microsoft account, they will be directed to a sign-up page to create an account."

Decoding it:

Guest access requires either an O365 account or an MS account. If a user does not already have one of these accounts, then he/she MUST sign-up for an MS account before being able to access a Group as a guest. As usual, it is possible to sign-up for an MSA using any email account, including corporate and consumer domains.

Correct?