People who would receive honorary degrees should pay honorary tuition
So many people can't even afford a degree they actually have to work for - either in terms of tuition fees, or in terms of the time they're not able to do paid work because they're studying.
To get far enough in life that you're being awarded a degree for having done great things (and you're well-known enough for a university to notice you), you must surely be able to afford to stump some poor kid up a few thousand so that they can at least work for what you got for free. I mean, maybe some people who are that highly renowned are broke, but surely most can't be too poor to even make a symbolic gesture.
It shouldn't be enforced by law; it should just be something people do, like tipping waiters.