There is a great Athletic article relating to this, so I've copied a relevant portion. The rest of the article covers the difficult decision of how to disperse tickets. Do they go strictly by donor amount, donor lottery, students only, etc. Some hard questions to answer.
That person works at one of the (Power 5) schools that sells out most, if not all of the time. This person has modeled dozens of different seating configurations in an attempt to maximize seating capacity using their state’s current social distancing guidelines. The best they can do given the current guidelines — which certainly could change over the next three months — is between 18 and 22 percent of capacity. This person has tried every possible configuration. The other big question all the departments are asking is how big a family unit can be. People living in the same house don’t need to stay apart because they aren’t apart at home, but a school isn’t likely to allow 10 people to form one family group. That number will have to be decided.
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While the mask debate rages in multiple states, athletic department leaders seem united that willingness to wear them could lead to greater stadium capacity. Whether that’s true remains to be seen. At this point, no state would allow even a half-full Power 5 stadium. The people who run college athletic departments hope that changes, but they need to be ready for multiple possibilities. So they continue to model different seating arrangements. They also are trying to troubleshoot in advance the issues that could arise from limited capacity.