So far I had never to testify at a trial ! I never was a witness to a murder, or a running away terrorists, I only know that from my little crime serie I watch on TV.
Sometimes I have to testify that I am really married to Mr.Black, because on my passport is writen Mrs White, but that's why in some European countries the wife keeps her maiden name from birth on until she dies. That's easy so if you marry 10 times you need no proof that you changed also ten times. On the other hand it's a little strange when a family composed of 4 children, a husband and a wife, the only one who has another name is the wife, because the children usually take their father's name.
Mr. G. had started to work in Italy, which is normal he is Italian, but then he worked some years in Germany, and since 1967 he works in Belgium. The result is that each year he has to go to the local resident's registration office to testify that he is still alive ! Otherwise he wouldn't get his pension from Italy and Germany. Then he has to fill in administrative papers, although nothing has changed from year to year and he still presents himself in person. At least it justifies that the administration works.
I could have signed a circular letter by our neighbors to testify that Mr. G. is still alive even when they don't see him, they can hear him, he has a very loud opera voice and doesn't need a microphone.
The state is so angeous that I could put his pension in my pocked when he has joined the angels or the devil and I could play the "Merry Widow" with his money and therefore needs the paper to testify that he is still alive !