In a world of more or less complete transparency between borrowers and lenders, very low transactions costs, and very low risk aversion, access to credit would not be rationed; and ex ante yields on financial assets, including loans and bonds, would not embody risk premia.
So if households and firms wanted to bring forward spending in the face of shocks to the economy, they would be able to do so restricted only by their need to remain solvent. But nobody believes that that is a description of the real world in which households and companies manage their affairs.