Hi,
On the "Add Event" screen under "Send Mail" there will always be a pre-filled To: address.
It seems highly likely to me that if an administrator provides a default list of addresses on the "Settings" screen under:
Reminders > General >Default list of recipients
then it is probable those people will always need to be informed. In that case the "Send Mail Now" box on the "Add Event" screen needs to be checked by default.
So my suggestion is that there should be an additional option for the administrator to set on the settings screen under:
Reminders > General
that if checked forces the "Send Mail Now" box on the "Add Event" screen to be checked by default.
Just an idea!