This will be completely different in the final game where there will be even more different stages of awareness for the people and how they react to you. In the garden they will probably only follow you around, to check what you are doing there, in a house they will try to throw you out or call the guards.
If you steal something, they will notice it, depending on how important the item was. Maybe they will never notice about an apple, but about the expensive sword on the table.
They will not know if it was you, but they will call the guards and rumors will spread around and people will get more sceptical around strangers like you.