You will know when it cuts in, have had it once when a flock of sheep ran out in front of me

, came to a juddering stop surrounded by them, but never hit one. I reckon without it the panic handfull would have locked the front and me and a few sheep would have had sore bits, so it works in my opinion. There is no doubt in controlled situations some people could stop quicker without it but in a sudden panic like that most would benefit from ABS.