The kids came to me with a contract dispute: they disagreed about what the deal had been. After some talking, and hearing what they each thought they'd agreed to, it turned out that the contract wasn't just metaphorical:

"Anna rents the living room from Lily in exchange for Lily's use of bedroom. And Lily will do free cleaning."

It turned out that Anna signed it after hearing a rough paraphrase. I told Lily that she would need to read any future contracts aloud, word for word, before Anna signed. I also explained about interpretation against the drafter, and how Lily should be careful to avoid ambiguity in writing down agreements.

I'm not sure what "free cleaning" means here? Generally they both do very little cleaning, free or otherwise.

Cleaning up this evening I came across a second contract:

"Anna will let Lily use bedroom and bathroom. In exchange Lily will let Anna use the living room and Lily does free cleaning. If furniture is moved or added please put away".

This one wasn't signed, so perhaps they couldn't agree?