If you screw-up royally in a match, how long does it take to get back into the good graces of the selection committee?
If it's an insurance company, could be forever. Especially if you have records from an MD who wrote some difficult things about you.
Basically, when an MD makes a note, it remains with you permanently. This could be beyond your MIB.
What did the ER doctor record about your last visit? What did your pediatrician write? What does your OBGYN say about you in your file?
Don't know? Really.
Literally, it's the difference between getting insurance, and getting declined.