I suspect that only time will tell. Certainly an AW on a solo machine, ie with no trailer, will haul the huge bulk of our own dear Greybeard up hill and down dale for many many years, and show no signs of falling to bits. Me and my trailer full of shopping weigh about the same as him
I routinely tow a 38kg dog on a 15kg trailer with an X-RD3 and on another bike with an AW, and three years in it's fine.
Pashley's advice about not towing a trailer can be ignored, in the same way that my shirt label that says "dry clean only" can be. It's just manufacturers covering their behinds, and Pashley are famously wishy-washy when it comes to specific technical questions
For really huge loads, such as those you might expect to lug on a Bakfiets (long), there are/have been specific cargo hubs that are beefed-up. The one remaining in production is the SRAM P5 Cargo, and in the past Sturmey have done specific beefy models for tandems. These days cargo hubs are hard to find; makes you wonder if they're just not needed.
But most hubs gears
that I've encountered survive perfectly well with trailers. My suspicion is that they won't explode with loads that most people are capable of hauling.
It would be genuinely and properly interesting though to hear if someone has damaged a hub gear hub lugging heavy loads, as I'd really like to see what happens to them
oh, and the reason we aren't here that much is that the Toggle thread got a bit crowded, so we have a separate side-forum to do it in finer detail. I still haunt this place regularly in case something catches my eye. I couldn't live without at least a weekly dose of this forum