Digitally Sign Ticket System Email
Have the ability to Digitally Sign (and encrypt) Ticket System Email. This will lend a lot a credibility to the email and cover all those people for the invoice by email requirement and keep things automated.
It also keeps the email in the inbox instead of the trash bin, junk folder and passes through spam devices with easy because of the high level of trust.
Having this ability can only be a win, win.