Solo victory points... "Hey there, I see you haven't raced in a month, so we're confiscating half your points."
Then ofcourse, you lose the race, forget all about it for a month (hello Abyssea 1-3), and BAM! "Hey there, I see you haven't raced in a month, so we're confiscating half your points." Ofcourse, you do not get refunded for the millions of gil you paid to join races to earn those points, only to see them vanish because you stopped gambling...

And ofcourse, the items used in the race.. you can only store one, so you end up with an inventory full of unusable junk only used for races you can do once a day.