It would be a great feature to allow you the option to send clients that their ticket is over due rather then just staff.  When you have loads of tickets in the system it's hard to keep track and it helps when clients get a message too so they can be reminded they haven't responded to a ticket yet.  While some people may think this would be annoying I think it's a great idea as some clients forget they're issues outstanding and need to respond to resolve them.It would be great to be optional of course just like the reminder for staff side is.