Not having previously heard of "dual sensor brake support systems" I looked it up, and why it can't be used when towing. The first thing that came to light was a reference to Suzuki models with dual sensor brake support systems. I found no other reference to any other make, though perhaps they might call it something else.
The second point specifically relating to towing was from New Zealand. And the description did not make any sense in the context of UK caravans, becasue it was discussing electric trailer brakes. Apparently with some electrically operated braking systems, the trailer brakes are only applied if the brake lights are illuminated. The problem might arise when descending long hills, where the car might be applying engine braking, but becasue the brake lights are not illuminated the trailer does not apply any braking, transferring all the braking effect to the car.
If you re read my opening sentence, I specifically limited my answer to vehicles sold in Europe and the UK, where electric trailer braking is not used .
The use of overrun braking removes the dependance on the brake lights being operated to cause the trailer to brake, so given a long hill descent the caravans brakes would apply as necessary.