Yeah maybe. And just the fact of filling in travel & accom means they can see you have confirmed plans to be there so minimises no-shows.
I'd hope if there was another air traffic control meltdown or something, though, they'd look to get an idea of numbers affected to inform some common sense...
I suspect it might also help them consider their options if a particular flight is seriously delayed and they expect hundreds of fans to arrive close to kick-off.