PTO Manager does allow more than 1 user to have the same email address. This is true if the users are within the same school or at different schools. When you enter an email address that is shared by another PTO Manager user, you will get the following message:

Warning: You have entered an email address that is also used by User Name from School Name: To proceed with login and create a new user, select confirm
If you are in the system more then once please contact your administrator to remove the duplicates.

This message is to try and prevent duplicate entries. If the user is truly a different user (or the same user at a different school) simply hit confirm.

Note: For users sharing the same email or for users who have the same email at more than one school - you do need a unique password for each login.