It works for me when I impersonate them in Blackbaud then click on the Pick-a-Time link. I've also impersonated them by typing in there email address when login into Pick-a-time. In Pick-a-Time, login with your login, go to Admin IU, Click on the event, In the settings tab, click scheduling link (for selected event). Once you click the link, you can type in a parents email address you want to impersonate. It's an added step to copy and paste the email address from Blackbaud, but it works.