I am aware EU citizens can stay in the UK unconditionally for up to 3 months, and permanently if they study, have a job or otherwise can support themselves.
That makes me wonder why UK Border Force officers frequently question EEA nationals? Not in the same way as with non-EEA nationals, but at Calais yesterday, it went like this:
IO: Where are you going to?
IO: For how long?
Me: 5 nights.
IO: Where will you be staying?
Me: The Arsenal Tavern hostel near Finsbury Park
IO: What do you hope to see in the city?
Me: I'll mainly be seeing a friend
[IO stamps the blank sheet I had asked him to stamp]
Out of curiosity: if, for example, I said I lived there as a student (in fact I was considering studying there for a while), would they usually require to see any specific documentation besides my ID Card (given that I'm an EEA national)?