Fully agree Dig, I often see straps used where I’d use chains. How many drivers can tie a Truckie’s hitch, these days? Not that ropes are legal any more.
Re securing a trailer atop of another, I’ve always chained between the dual on trailer and dolly, if no dolly, cross chained from the chassis/top of the legs. I’ve never had to do it, but if fitted with alloy rims, I assume a decent thickness of rubber would be needed to protect the rim from the chain.