Disagree on this one.
Hammer and bar with a bolt in place to protect the torsion bar end threads is the safest way to extract torsion bars without risking any damage to the end threads.
If done correctly there is absolutely no risk of the trailing arms moving or causing any disturbance on the bearings.
Pulling on the threads will risk damage, especially with the more stubborn ones whereby using excessive force will risk pulling the threads out completely.
Often the most stubborn end of the torsion bar is the ends which are situated within the trailing arm, which when being pulled on will usually happily remove the other end from its position in the beam but is more likely to pull the trailing arms off the pins that way if the other end is sufficiently stubborn within the trailing arm end.
As Kris is probably thinking many people when using a bar and hammer will try to extract the bars by hitting from the less accessible ends of the torsion bars, which with some agreeance would pose the same risk of disturbing the trailing arms as pulling would as mentioned above.
There is a much more effective/reliable way though