This reminds me of an interesting riddle ...
A man was sentenced to death. The death penalty will be performed at any time of the next seven days, the executions tells him on a Sunday. But it will be arranged in a way that it will come as a complete surprise.
The man sat in his cell, pondering about his odds.
"Well, as he said, it will be a complete surprise to me, so it can't be next Sunday for sure. This is the last of the seven days, so it won't be a surprise."
"Thus, Saturday is the last possible day. Which makes it unlikely to be, since I know it can't be Sunday, and if I'll be alive on Friday, Saturday will be no surprise anymore. So this leaves us Monday thru Friday."
But with the same argument, the man cuts off every other day from the list ... and realizes that he won't be killed at all. How lucky he is!
On Wednesday, the executioner picked him up in the cell, and he was killed. And he was utterly surprised.