At the end of S02 E08, "Rose", there is a conversation between Rose and Stefan inside of the library at the Salvatore Boarding House. How did she get in without being invited in?
I think before the Salvatores handed over the deed to the property to Elena, it belonged to them and since they were dead she didn't need an invitation. I may be wrong though as I cannot clearly recall when the transfer of the deed took place.
What do you think?