To date, no consensus has been reached:
http://forums.24hoursoflemons.com/viewtopic.php?id=3328
That's about as clear as mud, but that's where we are.
I suspect that if you have one that's so crappy that it makes you doubt the safety of the car, then replacing it is probably the smart thing to do. Just keep the old one around and bring it to the race so that if you get questioned about it, you can show the crappy, unsafe one to the judges and then they can decide.
(edit after reading Phil's post above)
Or, if you can't fit a ball joint in your budget, tough shit.
Pat Mulry, TARP Racing #67
Mandatory disclaimer: all opinions expressed are mine alone & not those of 24HOL, its mgmt, sponsors, etc.