Private emails

hello, 

after using the message 1.9 plugin to send a private message from my admin to another user  it seems the links provided within the email allow the recipient to login as the admin.  

specifically the email provides

        To view your messages, click here:

        http://XXXXXXXXX.com/messages/inbox/recipient

this link allows the recipient to login as the sending party. How can I adjust this 

thanks community