My dad said on many occasions that champions often gave less than their best in a non-title bout in the hopes that losing the fight would help build interest and the gate in a title fight rematch. While I doubt that it was often, as my father stated, it does seem a likely scenario. Do any of you know of any instances where it was purported or proven to have happened.
Nino Benvenuti was a prime example when he was World Middleweight Champion, he was stopped by Tom Bethea in round 8 of a non title bout on March 13 1970. But on May 23 1970, Nino stopped Bethea in round 8 of a 15 round title bout. Your Dad is right, sometimes it does appear that some champions take it easy on non title bouts to build up interest in a potential title bout when there is money to be made off of the gate.
Non title fights are just warm ups in my opinion, generally to keep a guys like Duran and Toney from eating up to 220. But I can see your point back in the day and I'd never considered it before now
Sugar Ray Robinson often carried guys. Perhaps didn't dominate as he could have because they want to sell a rematch for the title. I think Benny Leonard might have done similar.