People will just gather somewhere like we do for Euro aways if they don't IMO.
I find it pretty staggering that after being awarded the competition that more isn't done to make it a festival of football in that city. If you get a team where you're likely to get a lot of ticketless fans such as us, I don't understand why you wouldn't put on a screening really. A big screening where people can congregate together would keep fans of opposing teams apart generally apart, would give incentive for people who haven't booked pubs to not need to consider the bunk and would provide some great photo/media to show the world if goals go in (think Euro/World Cups).
The argument seems to be that they don't want to encourage ticketless fans to travel- but we know already that even conservatively we'll have 50% more than the allocation provided out there.
And that's just the screening - it'd be even worse if there wasn't some sort of fan park. I'm sure there will be, there was something for all of Istanbul, Athens, Basel, Kiev and Madrid.