I'm curious if anybody knows of other examples of how this mechanism actually works out physiologically.
Consider telomeres. The body's inability to repair telomeres can be considered as an adaptive mechanism protecting from tumor formation in early life.
A little thought experiment:
When you're a unicellular organism, you want to make as many copies of yourself as possible to maximize fitness. When you evolve into a multicellular organism, this strategy ain't working anymore. A multicellular organism with telomerase expressed in every cell of the body will eventually get a mutation in one of the cell division regulatory cascades which causes it to divide infinitely and kill the whole organism.
For this reason, telomere repair should be disabled in non-reproductive cells so that renegade mutant cells would run out of reproductive capacity and stop dividing. The only way large tumors would occur is due to 2 independent mutations: one for cell division and one for telomerase expression. This is vastly more unlikely. The downside is that lack of telomere repair would lead to gene deregulation and eventual aging.
I'm fascinated how well this thought experiment parallels the story of Rasputin - a self-proclaimed healer who got into the inner circle of Czar's family by helping their sick child and then worked to expand his influence. In the end, a group of nobles decided that the influence of Rasputin was threatening the empire, so they poisoned, shot and drowned him. Blood in the water indeed.