ad far as i know they wear the green turban because of the color of the Gunbad of the Masjid-e-Nabawi. the idiots dont realize that it was not the prophet who built that green Gunbad, but rather it was done much later by Zangi ( i think it was Nooruddin Zangi).
they also go to mazaars etc. and i have been told that they keep an empty space in the front most row while praying because they think that the Prophet is still alive and prays with them when they pray.