For Mises or Rothbard, it is simply confused to posit latent preferences; if two individuals fail to make an exchange, then this ipso facto demonstrates that at that moment at least one of them would not have benefited from the exchange.
by that very fact itself. compare: eo ipso.the oxford english dictionary (2007)
Silbentrennung
by that ve·ry fact itself. compare: eo ipso.the Ox·ford Eng·lish dic·tion·a·ry (2007)