Free college sports tickets = build the cost into the student fee, but yeah. I guess you you could make the 'Dog Pound Die Hard' tickets free, so long as the kids get there on time. I guess the best way to check when kids leave is give them a code to text after the school song is sung.
Actually this is pretty doable.
Free = not valued. The GHO used to be awash in free tickets, for many years couldn't give them away even with hospitality access.
There should be a nominal charge and if you want to use that money to pay for swag (t-shirts etc), to refund for attendance, food vouchers or other incentives. I don't know what student tickets cost these days but I'd be shocked if it were more than $100 for the season.
I think one incentive is to form tailgate clubs with prime real estate and maybe some permanent facilities. Again, other schools do this.
The first thing to do is start an official student supporters club. Do it like the American Outlaws do it, Tifos, marches, flags. Heck, let them escort the team on the Huskywalk. You just need some students/staff to lead the thing.