“There is baalus, because if the siddur is put down – no one can grab it (or if you stand for Boruch Sh’Ama”
Great points, but מהיכי תיתי? ( and nice comparison reagarding פאה)
Perhaps one may grab it and there is nothing you can do, other than say the one is lacking in Midos?
If you read the first link i posted in YD regarding ones rights to a השתמשות in a shul, you will see its not so simple what status one has, as far as baalos goes. It most likely works with שותפות and ברירה, meaning it is yours as a partnership as long as you are using it, but that is NOT a kinyan, it is only an indication like ברירה on the existing shutfos..