It's important to remember the words spoken by the legendary Warren Buffett a few years ago:
“Audit committees can't audit.”
The role of an audit committee is not to study every expenditure, gift or detail.
It's also worth noting the difference between the role of the management team on the one hand, and that of the board of directors on the other. The management role is to propose measures and implement them. The role of the board of directors is to monitor and approve how things are being done.
The volunteers on the audit team can't be familiar with all the details of every gift in any given year. To my knowledge, that's not done by any organization.