I don't think announcements help much on its own. You need physical guides, signage, proactive crowd control et.c.
Just like FFlash says.
Maldesign - Finavia did not provide the right infrastructure
Poor vision, lack of execution and failure to understand - "Priority boarding" is a desk product, planned without knowledge of actual boarding process. Implementation seems to be focused on keeping boarding agents passive ie technology is there to replace humans, not to assist them.