I suggest we stop the combative posts right here. This isn’t that sort of forum.
To answer your first question, I doubt there are enough Olivers on the road or for long enough for insurance companies to have evaluated their relative risk and be able to offer discounts. And I doubt that the market is valuable or competitive enough for them to do so anyway. Frankly, I wouldn’t look at insurance rates to tell you how roadworthy one trailer is relative to another.
Likewise, you will have to accept logic and anecdotal evidence for the stability and strength of Olivers. If you need statistics to make your decision, then you’re going to be out of luck since none exist. As posted earlier, we do have evidence of one Oliver that slid into a bridge railing in the snow, which did flip and I understand was able to be repaired. We also have stories of a bear unsuccessfully trying to get in an Ollie, though I have to question how motivated of a bear it was, lol. Plus I think it was trying the wrong door if I remember the story.
As for stability, all I know is that I’ve had zero issues and have heard nothing but the same from other owners. I’ve never read nor heard of anyone encountering sway with an Oliver, regardless of what tow vehicle they use. That doesn’t mean it can’t happen, but it’s good enough evidence of their stability for me.