Cornies are stainless steel. Nothing in beer can hurt them. I just finished my 2003 barleywine. It was in the keg for over six years and the keg is fine. I plan on replacing the o-rings, just because of age.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk