JuVDC
Ticket Filters override whatever the Agent inputs. Meaning if you have a Ticket Filter that sets a Department to Department C, an Agent fills out the new Ticket form, sets the Department to Department A, and the new Ticket matches the Ticket Filter criteria the Ticket Filter will override the Agent and set the Ticket's Department to Department C.
The Target Channel option of ANY will make the Ticket Filter scan all new Tickets regardless of their creation channel (ie. Email Fetching, Email Piping, API, Client Portal, and Agent Panel). This obviously doesn't meant the Actions for the Ticket Filter will be applied to all Tickets as they have to meet the Ticket Filter's Rules (criteria). This simply makes the Ticket Filter available to all new Tickets created in the helpdesk.
Cheers.