Hi,
if you have two or more browser, and on first browser (Main Browser - in my Chrome) have log User1 and on second (IE) User2, and with User2 send request for delete accound - to yours email income confirmURL - and now problem. If you CLICK on this confirmURL - link is opened with MAIN BROWSER in Windows (so for me Chrome) and DELETE User1! Not User2! You must copy link and paste to second browser, when you login with User2...
I think confirmURL must be paired with User Login Data. And better is if you have after click to confirmURL, show confirm screen with YES, or NO - delete account...