I am working on sharepoint online inside office 365. and i configured the following setting for our site collection external sharing:-
now let say i shared the site (add external user to the members group) with this account
firstname.lastname@example.org or account such as
1***23456789@XY**.com. where this external user will receive an email invitation with the site link.
but my question is, in theory could any other external user, reuse the invitation link, and access the site?? or at the end the sharepoint site will check if the external user who is trying to access the site is the same as the user which the invitation email were sent to (or at-least will check if the user has already been sent an invitation email)?