I had posted a question on a Keystone RV forum about what it says in the owners manual about not stepping on the slide out floor when it is retracted. Someone called Keystone and confirmed that that is their advice. It's not recommended to sit at the dinette or on the sofa either when the slide is in because it might cause damage to the unsupported slide out floor.
I didn't know this and am a little disappointed because we were hoping we would be able to take short breaks on the road without having to put the slides out.