The NCAA is left in an unusual position with the kids who have already signed with agents. I'd expect to start hearing stories and reports with suggestions of some kind of waiver for 2020: if you signed and didn't receive money or if you signed and did receive money.
That is coming. This year is unprecedented - they will let kids opt back in who have signed with agents. What the conditions are in terms of repaying benefits remains to be seen, but I highly doubt they limit the ability to opt back in given the circumstances.