I have a 10-year-old greyhound (adopted from the racing world in the last few months, who we insured very shortly after adopting). PetPlan's claim forms say that you must provide medical history for the last several years - in my case, no such medical history exists because of where our pet came from. In lieu of almost 1 1/2 years of history, they accepted the adoption paperwork and what medical history I had (maybe 1/4 of what they require). While I definitely do not recommend that anyone withhold any required paperwork, this was an unnecessary worry for me, because PetPlan obviously understood that I don't have any of my pet's prior medical records. There was no delay in processing the claim; in less than a week, I have the check in hand. The process was quick and easy.
I hope I never need to file another claim, because to do so means my pet is sick or has been injured. But I know that if I do, I won't have to worry about the insurance claims process.