Perhaps I missed something, or maybe it isn't possible. Is there a way to make ticket submissions not require a child type when the user submits a ticket? Going through testing shows that it's a requirement.
It will if a Child exists on a Parent. If the Ticket is coming from say E-Mail, then have a Request Type which has a single level, assign the Inbound mailbox to that level the the Tech, part part of his/her procedures will do some sort of triage to re categorize accordingly.
If the Ticket is generated from the Client UI, then they will have to enter these required fields.