Not a huge Julia fan but I have to take her side on this one.
It's not the in laws bedroom!! It's a damn guest room…to be used for guests.
Imagine her thinking that the room would be left vacant while Julia's parents are cramped in other spaces just so she could have a place to sleep when she "visits"?
I don't even think they belong there while Julia's parents are here…aside from a visit to meet them and welcome them to the states, they need to give Julia some time with her parents. It's not like Brandon's parents actually want to build a relationship with them… SHE'S just being nosey.