If we go with the current guest subscription proposal, in addition toYes. For my primary use cases I'd more likely create a normal subscription (but I do see where following only their own thread would be a useful choice in some cases).
As part of this, anyone who is subscribed this way will have to reply toHmm, no.
In my use case I would want their default (say they just reply to the confirmation email) to be the option I chose. So I think both buttons would still be needed.
Providing the option in the confirmation email is probably a good feature anyway, for those new members observant enough to use it. I'm not sure what form the choice would take in the email, but if it is a control that has a default then its default should match the button I chose.
Also, is it important to have these subscriptions marked as special inNot for me, I think. I can sort the Members list by Joined date to readily find any new ones, and if I'm concerned with an old one I probably know the email address or something I can search for.
But if it is in the Members list I'd want it to be searchable and sortable. That is, I can imagine use cases where it would be handy to bring up a list of just such members, or bring them to the top of the list. And of course be in export as well.