Not true, majority cars with Auto-hold feature (even with Auto-hold turned off) will apply brakes for few seconds on inclines to prevent car rolling backwards. MG doesn't roll back, we just came back from trip to China border and had no issues. Also owned BMWs with DCT, they don't roll back either.
The way to activate is to come to a full stop using the brake pedal. Also NEVER use accelerator to hold position on an incline in a DCT vehicle, that's the fastest way to overheat and damage the DCT transmission.