That problem extends to renting the week too. The renter sees it as a hotel. Late cancel can cause loss of CUP points.And this is why I don't tell friends about the timeshare. None of them treat a timeshare reservation with any gravitas.
They have no idea what a pain canceling, changing and similar are. So they treat the week like a booking at hotels-dot-com. "Oh, I'll just cancel! I'm giving them 24 hours notice! No big deal!"
It happened often enough that I treat my Hyatt week like I treat my tools -- never loan them out.
I do hate how Hyatt nickels and dimes for transactions, including changes to the guest on the cert... but it is what it is.