If you want to send email to the requester, in the User/Group in fields, you can select the field which holds the user value.

If you want to send email with user in CC, you can use script 

if(current.getValue('u_drop_off') == '1' {

    var dropOff = gs.getProperty('Location');

    email.addAddress('cc',dropOff);

    email.addAddress('cc',current.requested_for.email);

}

Can you also confirm, your notification is on sc_request table?