Quite often, we input client details from hand written forms they've filled in. Sometimes their email address is hard to read and we have to make a guess on characters.
I've noticed that when we get the email address wrong, we have no idea if the client is receiving the ticket emails. The only indication is when the client informs us they have had no comms from the ticket system.
It would be very helpful if we received an NDR should an email not reach the recipient.