What had the two fugitives been doing to get into trouble?

The younger man reveals that he was selling a kind of toothpaste that accidentally-kinda-sorta took the enamel off people’s teeth.

The older man got in similar trouble for running a scam himself. He ran a "temperance revival meeting" (which is much like Alcoholics Anonymous, except without the anonymity and it’s actually more a scam than helpful in any way) until it got out that he was quite the drinker himself. So that was that.