I'm missing "if a person confirms they are in control of an email address it will always be theirs" recently got bitten by it as it dept recycled email addresse

I'm missing "if a person confirms they are in control of an email address it will always be theirs" recently got bitten by it as it dept recycled email addresses so a new hire got email address of somebody who left some time ago. They got some of their privileges. Oops