When you are setting up a corny keg, you should crank the output pressure to about 30 psi to properly seat the seals. Then you can turn it back down to your carbonating/serving pressure. You don't have to leave at 30 psi, just crank it up once to get the pressure in the head space and then turn it back down.
"Beer is proof that God loves us and wants us to be happy." - Benjamin Franklin (not really)
Blaine McCormick of Baylor University says that this likely came from a letter sent to Abbé André Morellet in 1779 about wine (the miracle of water into wine) where Franklin says, "Behold the rain which descends from heaven upon our vineyards; there it enters the roots of the vines, to be changed into wine -- a constant proof that God loves us, and loves us to be happy."