Both my cars have this feature; a 16 plate Audi A4 (being replaced by a Golf GTI PP DSG next month!!), and a 17 plate VW Touran.
My Audi gets caught out by sudden changes in the slope on roads, causing the brakes to cut in briefly. Sometimes this just happens with no audible warning. The car also bleeps at me if I approach a bend where a car might be parked on a side road. It thinks I am heading for the parked car, beeps, and then cancels the warning as I follow the curve of the road and the parked car disappears from sight.
However, I have had one really scary experience. Driving on a country road, I rounded a corner where there is a lay-by on the left. A coach was parked in the lay-by, and my A4 clearly thought it was a solid wall or something. The car pinged, I kept on driving as I had no intention of crashing into a bus parked off the side of the road in a lay-by. However, I think the radar continued to sweep along the side of the large coach as I was rounding the bend. This convinced the car that I was asleep at the wheel and destined to crash, so it applied a full emergency stop.
There was nothing I could do. I stayed in my lane on the road, with the bus entirely off the road in the lay-by to my left. The car screeched to a halt, and thankfully the woman behind me was far enough back to stop without rear-ending me.
Lord knows what the drivers behind thought! The bus driver was out in front of the bus, stood in the lay-by. He looked at me like I was deranged.
I took it to my Audi dealer, and they applied a software patch to the AEB system. It still pings, and snatches at the brakes from time to time. But, thankfully, no full emergency stops since.
I have only had one pedestrian step out in front of me. The car snatched at the brakes for a moment, then the pedestrian jumped back onto to the pavement.