I remember when I went to the UK for the first time, I knew the language, but was never confronted live with a London accent. I did not know the postal code sys

I remember when I went to the UK for the first time, I knew the language, but was never confronted live with a London accent. I did not know the postal code system(every little borough out there belongs to London, but has zones and postal codes) , nor did I know the public transport options. I simply went there to visit a friend which had moved there, that is all. So just before the transit area after coming off the plane, a ginger and a brown haired fellow stopped me and started asking questions, without showing a badge or identifying themselves. They were plain clothed officers, guessing they are police was rather easy, they had very bad choice of çlothing style. So they ask where are you going and why. Purpose of stay and lenght, how will you get there and blabla, many follow up questions. Do you have a return ticket, whats her name. I told them, thats your job to find out and I intend to travel by cab, am I good to go now. They let me go on my way. This is the kinda people who will be dealing with our data, hell no. I will fill out whatever if I ever wanna go to the us, but I prefer to not hand over any data upfront.