Quick registration is the new way of registering for an event. In the past, Guest Checkout meant that if an attendee did not complete their registration, they would be classed as "Pending Acceptance". This, in turn, would mean that some people would not complete their registration and therefore would not attend the event.
If you register for an event without logging in all you need is to do is enter your name and email address, and you will be registered without needing to verify yourself.
Registering for an Event before it is Live
When you find an event you would like to join on Hopin, or if someone shares an awesome event that they'd like you to join, simply click on Register to get started.
In the new panel that pops up, you can select how many tickets you want to claim and click Continue.
On the next page, fill in the fields for the name(s) and email address(es). If you are signed in, you can click the box at the top to automatically fill in the fields, but you will need to complete the information for anyone else you are claiming tickets for. Make sure you fill in the correct email address! Click Continue when you're ready.
Once completed, you will see another page to confirm the tickets and the emails they are being sent to.
Head over to your emails and you will have two emails in your inbox - one will include an Add to Calendar button to add the event directly to the calendar of your choice, the other will have a Join event button to take you directly to the event.
Joining or Registering for a Live Event
If the Event is live and you have already registered, then you should have received a registration email. Click the Join Event button within this email to go directly to the event.
If you cannot find this email, or perhaps you haven't registered yet, find a link to the Event that will take you to Registration page. Click Join Event.
In the pop-up, enter the email address that you registered with and click Send me my access link. 
If you have already registered for the Event then you should receive an email with a link directly to the Event.
Alternatively, you may want to Register for the event if you are not sure if you have already registered, or Sign in to your Hopin account to join the event.
Register for the Event
If you are not sure if you have already registered, you can click Register for the event and you will be prompted to fill in your first and last name and your email address. Here, you can also click Sign in if you already have a Hopin account.
Once you have filled in the details, click Register.
Head over to your emails and you will have two emails in your inbox - one will include an Add to Calendar button to add the event directly to the calendar of your choice, the other will have a Join event button to take you directly to the event, if the Organizer has enabled them.