If someone wants to really test this, get 2 people to open 2 independent accounts. Find some place where you can trade side-by-side with very dissimilar IP addresses. Set up a video camera to cover both computer monitors and open trades in the opposite direction on the same pair during fairly quite market times. Set your stops about 20 pips away and watch what to see what happens. This would be an excellent test to try on any number of brokers.