Before adding a new person, I issue the viewPerson command to search for them based on email address. Copying the email address of an existing user and pasting it into the command strings below I get back a null set when I should get back the user.
cmd=viewPerson&sEmail=brandy.cangelosi@ddb.com&token=[removed]
cmd=viewPerson&sEmail=brandy.cangelosi%40ddb.com&token=[removed]
I have tried it with the email URLENCODED and not, and with the email address all lower case (shown above) and with the case matching what is in FogBugz.