The $100 is if you're not offered a Plat amenity at check-in. Per T&C, you must raise the issue before you check-out.
It's not due if they offer you amenity but then the points don't post. The remedy there is just the points.
JW Mall of America refunded me $100 earlier this year though they technically were not required, as I did not realize I hadn't been offered an amenity until after I checked out.