Two separate questions: Should we? Absolutely not. Does it work? Yes.
If not, how did the German’s role up all of those resistance networks in France? Did those captured all of a sudden realize that the Nazi’s were not such bad guys after all and it would in fact benefit their compatriots to provide their names and locations? Did the Catholic missionaries in the USSR (see Fr Walter Ciszek) all of a sudden discover that the Soviet Union was paradise after all and therefore decide to turn in the names of their brothers? (And since such actions were incredibly successful, we must assume that those being tortured did in fact provide accurate information. If not, and they merely parroted their captors suspicions, then those who were really agents would have been able to operate undiscovered since those suspicions would have been no more than random guesses. The first rule of espionage: always pick the agent the other guy would never suspect.)