How does one loose control?
Several answers
Happened to me ONCE, did not roll, recovered but with damage. turns out the lugs on one of the trailer tires was loose and when I cornered (on gravel) there was enough "Flop" to cause it to break free and slide into the ditch.. Thankfully it was a PUP so with the low center of gravity only minor damage (Dent) no roll.
Next trailer I had was not stable.. We ended up doning multiple things (re-distribution of weight adding a stablizer (Reese friction sway bar) and it settled down but without mods it was downright scary,, Never lost control, Never hith 55 MPH either. (before mod)
Too much trailer, Too litttle tow vehicle.. I see far too many people using an "F-150 class Truck to tow an F-350 class Trailer.
Brakes! I don't need no steenking brakes on that trailer.
Tire Inflation.. A underinflated tire reduces control (See loose lugs) in the same way my loos lugs did. Many people do not scale and use the inflation level specified on the sticker (Which in my case is too low)
Others Inflate to the maximum mentioned on the Tire Sidewall, which in my case is correct. But often is not.. This too reduces control
My Wife, driving a JEEP (no towed) wandered off the edge, over corrected getting back on the road (She had a tendency to do that, approached everything as a battle) Zig Zagged a couple times across the road and smacked into a tree at 50 MPH..... (if she had accepted my suggestion of a closer camp;ground she would still be alive today, Oh well).
There are many ways to loose control.