OK, I realize that testing 75-year-olds doesn't make scientific sense. But, here are a couple of thoughts.
First, I'm a few years younger than 75, but it has been my observation (in no way scientific) that no generation in the history of the world has had a greater feeling that we just might live forever, nor a greater shock at realizing that, just like every generation before us, we will actually grow old and die. We were part of an enormous youth movement. Heck, many of us still listen to "oldies" on the radio station, music that is more than half a century old, re-living those teenage years in our memories. The idea of growing old just doesn't sit well with us. And so, even at 75, many of us don't consider ourselves "old," and we hope to live for many more years. And some of us will.
My second observation is that testing a 75-year-old probably doesn't make sense to a guy in his 40's or 50's, but it might make sense to that same guy when he himself has become a healthy 75-year-old. I'm 68 now, but despite having had cancer I'm still enjoying life and still feel active and involved. Some guy who's 75 and has never been sick a day in his life (unlike me, who has been taught by a cancer diagnosis that our existence here on earth is definitely finite) is going to have a hard time accepting the fact that he might have cancer, but that he shouldn't be tested to find out. Maybe one has to actually BE 75 to understand that.
Does it make statistical or scientific sense NOT to test? Sure. But do we as individuals give up on life and resign ourselves to the ash heap just because we've reached a certain age? Ask that question of those 90-year-old WWII vets who are willing to crash their way into their Memorial in Washington, D. C.
So, I fall back on my "freedom to choose" argument. In other words, it's a mystery to me why so many people are adamant about a woman's "right to choose" regarding health care, but are unwilling to apply that same argument to other areas of healthcare. (I'm not in any way directing criticism at you, Jeff, or trying to imply that you feel a particular way, just wondering in general).