Actually the self-destruct devices were tested before each U-2 flight. It’s just that 70-second interval wasn’t always the same, the deviation could reach as much as 5 seconds either way.

Yesterday was the 54th anniversary of the first spy swap. Francis Gary Powers walked past Rudolf Abel in Germany. If you’re interested I wrote my own article about Powers, the famous U-2 pilot. It’s available here:

That’s what Napoleon thought in 1812 and the Nazi Germany in 1941. Both were defeated. Why? Because Russians have a bad habit of reorganizing in a hurry and throw everything (and everyone) at any threat to them. Stalin said the words he said for a reason.