do you have to sign a ticket in missouri?
If your question is, "is not signing a ticket a defense that will throw the ticket out," no it will not.
No. Signing a ticket is just your promise to appear in court. The case goes forward whether you sign the ticket or not. If you don't show up in court or hire an attorney to take care of it, a warrant will be issued for your arrest. If you haven't done so already, I'd advise you to hire an attorney.