On the Citroen C3 semi-automatic (electric clutch), if you left-foot brake whilst the throttle is still open there is an almighty thud from the transmission and the engine goes down to idle rpm, leaving you stranded in the middle of the road for a minimum of 30 seconds. The dealer from whom I got the car said, 'why would you want to brake whilst accelerating?', to which I said 'to keep the engine alive but shave a little off the speed' and they refused to accept that that situation could ever arise. Which is more dangerous, LF braking+throttle, or being stranded in front of a 32-tonner whilst the ECU sorts itself out?