Mulana Manzur Nomani R.A. in his book has clarified that Actually in Tabligh people of all levels are their.
In words of Maulana Ilyas it is platform of a washer man so all types of dirty cloths will also come.
So it is obvious that mistakes will be. It is actually a Place of Washerman where very dirty Cloths also come. From the book Jamaat Tabligh par Aitarazat ke jawabat
One detail Answer of some misunderstanding has been written by Maulana Manzur Nomani Writer of Maariful Hadith in Urdu.TO see please click the link http://tablighijamaattruth.blogspot.in/2012/05/maulana-manzur-nomani-writer-of.html