I have manually synced the subscriptions records with a downloaded report from PayPal. All subscriptions known to PayPal to be active should be marked as active, and all subscriptions not known to PayPal to be active should be dead. The active subscription count dropped by nearly 300.
If you disagree with the state of your own subscription, please let me know. I did not send email to each subscriber because I think this information is mostly redundant.
This afternoon, I thought that I had found a PayPal API that would allow us to query the status of a subscription. I implemented a quick test, and as I was almost ready to try it, noticed that I had discovered this same API over a year ago. It does not work. A quick google revealed that PayPal has still not implemented this basic API feature for subscriptions.