If I'm a wealthy supporter, I'm not going to personally deliver bags of cash.
I'd have go betweens obviously, maybe two levels apart from me. And the U isn't going to want to find out it was me that hard. I'd be donating millions a year, or whatever.
Plausible deniability.
I recall some scheme where players stayed in town over the summer and were given "jobs" at car dealerships or whatever and they didn't have to show up, ever, but got paid handsomely. There are a lot of ways to "influence" 19 year olds.