[Eomer of the Rohirrim]

I believe that, once you see a Warg, you fully realise what you are seeing. I don't think people can be tricked into thinking they have seen a Warg. Much like anyone who saw Gandalf could tell that he was a being of great power.

I remember when I first saw a Warg. T'was a warm evening and I was strolling through the moors some miles from my home. There was a figure standing atop a hill , probably a half mile from where I was standing, yet I could instantly tell that it was a Warg. It was as if an angel had come to my side and said "Yes, my son. You have indeed set eyes upon the most noble of God's creatures."

To use simile, it is like a veil is lifted from before your eyes, and you see the truth. If you did not feel this way Amariden, then it probably wasn't a Warg. If you did, then congratulations!