Law / EU Citizen without Karta Pobytu [2]

Hi,
I am a 20-something English girl who has been living in Poland for the past two years. I have never got round to bothering to get a karta pobytu, but the past few times I've flown into Rzeszow Airport I notice that the immigration staff are beginning to scan passenger passports. What info do they get? Can I be refused entry or arrested for not having legalised my stay? Will they even know I don't have karta pobytu?