Mishna Berurah (14:16) writes that people are accustomed to finding a siddur in Shul and using it in order to daven. He comments that he does not know the heter for this. Why is it different than seforim, which the Rema rules that it is forbidden to use someone elses without their specific permission for perhaps you will tear it during your learning.
Aruch HaShulchan (14:13) rules that it is permitted since the majority of people are not particular regarding this.
Aruch HaShulchan (14:13) rules that it is permitted since the majority of people are not particular regarding this.
