Steve,
A good many of us do not go into a casino only looking for one card on most occasions. As I indicated in my previous post, the many variations make that senario problematic. Also, not everyone has a large collection. We need a lot of the variations. Looking over any card while harvesting is one of the things that may well attract the unwanted attention we all wish to avoid. Unless there is a new front design many of us will not know if a specific card is a new variation for our collection until we can review it in detail and in many cases compare it to other cards in our collection.
I agree with the "care and caution when harvesting" part of your post. That is exactly why I will continue to Harvest whatever I can find, Leave the casino, and Review later away from any possible security.
Paul