I have to disagree with you. They are designed to take excessive force, they are there to protect passengers from whiplash injury (https://en.wikipedia.org/wiki/Whiplash_(medicine). Let say a 100kg passenger sits on the back and there is a crash the headrests will simply collapse during the force of the impact causeing the passanger death or spinal cord injury. My kids are 20kg each, so doubt that they cant tear it off if they can then there is a manufacturing defect right there.
Also see skoda manual http://ws.skoda-auto.com/OwnersManualService/Data/en/Rapid_Spaceback_NH/11-2014/Manual/Rapid/A05_Spaceback_OwnersManual.pdf
page 70 and i quote"
WARNING
With seats occupied, the respective head rests must be correctly set (may
not be in the bottom position) - there is a risk of fatal injury!"
So this is a very important safety part of the car that is why I am so uptight about this.