Hi OBG,
I had a feeling you were going to say that and I think you are correct!
The storage yard is in a rural industrial park surrounded by 5 other large companies with lots of traffic around. It would be easy for a person to slip-in to our compound unnoticed, as long as they did not go through the front gate (they cut through the rear fence).
A year after the generator was stolen we lost a Honda ATV the exact same way, DUH!
I now store only my largest work equipment there (e.g. boats on trailers, trucks), the more portable items I store at my residence.
Mike