Well, it wouldn't if all c24,000 season ticket holders had responsed.
But from a sample size of 156 as I type this, with a confidence level of 95%, 56 respondents saying "no" gives us a confidence interval of under 10%.
So that indicates between 25% and 45% of STHs won't be attending tonight.
Without wishing to sound like a headmaster - if you have one infection in the house already (maybe your son is old enough to not live with you), please test yourselves before you head to the game.