You can easily tell people's immigration status. I walked into my local Lidl about 7 years ago and didn't hear an english voice for the entire 30 min shop. That was the first time I realised how out of control immigration to the UK had become.
I voted remain, but if you think we can't tell who's english, or you think it's a lie that huge areas have been ghettozied in virtually every major city, you're either blind or unobservant or simply don't have a diverse contact with many areas of our society.