I don't think you're calling me out but perhaps pointing out differences between the American and Canadian U-Haul tow dollies.
I think we might both be correct for our respective locations:
Pennsylvania doesn't require brakes until trailer GVW exceeds 3k lbs.
Michigan is also 3k lbs.
Alberta needs them at 910 kg (2k lbs).
I was out and about today, so stopped at the local U-Haul and looked at the local dolly.
It absolutely has surge brakes; it's got a break away cable that goes with them too.
Given U-Haul's restrictions on how much vehicle you can put on a dolly, you probably can't get dolly GVWR over 3k lbs; but you can definitely exceed 2k. Surge brakes is probably why they lose the pivot - can't have the trailer jack knifing while its trying to apply brakes
The pads for the wheels are about a 1 foot ahead of the trailer axle (wheel size dependent); the coupler center is approximately 7' ahead of the axle. Close enough to 15% for girl I go with. Hitch wasn't exactly light - over 100 lbs, add 15% of front axle of whatever you're towing and it'd be heavy.
I'm going to call it, we both learned something.
@rusty ol ranger : Apologies if I added confusion - wasn't aware of the differences.
I agree with you, chain to the axle, not the frame. If the axle comes off the frame, you've bigger issues.