Based on a character by Reginald Bretner, this was published on the groaners listserv.

It was Ferdinand Feghoot who, in 2839, averted the greatest fraud in all history. The twin worlds of Gyppo and Pigeon Drop had the highest mutation rate ever known. Their inhabitants provided freaks for the galaxy’s sideshows, and specialized in revolting “wild man” acts, swallowing live hair-slugs from Lovecraft 14, and biting the heads off wet, wriggling slurbwinders. They were notorious for their rigged games and elaborate confidence tricks.

Then they abruptly “reformed.” They joined respectable churches, confessed every detail of their past swindles, and impressed everyone with their fervor. Soon ministers were giving them character references; bankers and lawyers were co-signing their notes.

Feghoot remained unconvinced . Though reviled and ridiculed by the popular press, he pushed his campaign for a thorough investigation by the Galactic Intelligence Agency to a successful conclusion, and the results proved how right he was.

The Gypponians and Pigeon Droppers had planned to salt their deserts with priceless gaborium, to sell mining stock everywhere, and then to evade prosecution by taking advantage of an obscure immunity clause in the Grand Charter.

“Tell me, how off earth did you know it?” asked the President General, as he hung the supreme decoration around Feghoot’s neck.

“It was obvious, sir,” answered Ferdinand Feghoot, “Beware of geeks baring grifts.”