Guest Checkout and Merging Duplicates

I've re-read the documentation a few times but I'm not seeing an explicit Yay or Nay about this.

We're on TNEW and looking at turning on Guest Checkout. I understand this it will create new accounts that have a Guest Checkout indicator on them and we can suppress these folks in lists and all that fun stuff. But what I'm not clear on is whether or not we can merge a Guest Checkout account with a regular account and still maintain that guest checkout functionality for that specific email address?

For example, if a donor or subscriber decide to make a new donation or purchase online using a new email address and guest checkout, we want that transaction to be on their regular account. The easiest way to do that would be to merge them rather than haphazardly trying to move them from one account to another. 

What I'm not clear on is what happens to that Guest Checkout flag once a merge happens? If it is maintained, is it still attached to the correct email address? What if they have multiple on file? What if they do additional guest checkouts using more email addresses and they also get merged? Or does is remove the guest checkout flag and they are no longer able to do that in the future using that email address?

If you have this function enabled can you please share your process with me? 

Thanks very much!