^ Quite right, Duncan.
I've towed many, many thousands of miles with simple hydraulic over-ride brakes on heavy trailers (2 tons+) - they work fine.
Just like towing or driving anything, one needs to drive sensibly and within the limits imposed all round.
Never brake hard, and specially don't brake hard going down hill at speed.
In fact, if the trailer has become unstable/weaving, don't brake at all - accelerate ... The latter will stabilise the trailer, allowing one to slow naturally from that point.
Always allow lots of extra stopping distance.
All pretty much common sense with light trailers.