Why did I not observe this problem before? There are two possibilities: Either I am becoming weaker, or I became better at escaping. I think I became better at escaping. There is a way of escaping from method 1, that I was not aware of before. On the right hand (where are no locks), one can move the chain to the place where the arm is thinnest. This is approximately 7 centimeter above the wrist. Then, using quite a lot of force, it is possible to pull the left hand out of the chain, unless the chain is really very tight.
Even if you pull the chain tight enough, there could be still some remaining doubt about escapability. That is not acceptable, because in that case the tied person will possibly try to escape, which may possibly hurt him. It is much better when the tied person understands that the tie is inescapable, so that he (she) will completely surrender and do nothing that might possibly hurt him (her).
When it is time to tie your hands, prepare a chain (mine is appr. 1 meter long, but it probably can be shorter) and close a padlock on one side of the chain. (This is shown on point 2) This chain you will put around your wrists, so that they are tied together. You will close it with a second lock. The trick is that when you put the chain around your wrists, it goes through the key rings of the bracelets. (see point 3 on the drawing) This ensures that you cannot move the chain over your wrists when it is locked, even when it is quite loose. You will also not be able to touch the key rings anymore, so that there really is no escape.
Here is a drawing of the procedure: