YES IT IS RUDE.
How, presumptuous of her.
It is NOT her home.
I REALLY HOPE... she does NOT have a key to your home, and that NO ONE gave her a key!
Start, LOCKING your door!
That is the easy solution... to STOP her from walking into your home whenever she wants to.
She can walk into the door, because it is unlocked.
You should be LOCKING your door.... and it is for general safety too.
If SHE can walk into your house anytime... then that means, strangers and criminals, can too.
Just lock, your door.
It is YOUR house.
It is, safety.
And if the woman grumbles about it, well too bad.
You or your boyfriend, just have to LOCK your door.
Or tell her, it is rude.
No brainer.