Some pilgrims camp outside the boundaries of Arafat and remain there until the sun has set; then they depart for Muzdalifah without standing at Arafat properly. This is a serious error which invalidates their hajj since standing in Arafat is the essence of haji, and it is obligatory to be within its boundaries and not outside them, if it is not easy to do that, they may enter before sunset and remain there until sunset. it is quite acceptable to stand in Arafat during the night of sacrifice in particular.
Departing from Arafat before the sun has set is not permissible, because the messenger of Allah (peace be on him) stayed at Arafat until the sun had set completely.
Struggling through crowds in order to climb Mount Arafat is not permissible, because it causes much harm and injury to others. The entire Plain of Arafat is a place of standing, and neither climbing Mount Arafat nor making salah there has been recommended.
Making supplications facing Mount Arafat is incorrect because the sunnah is to face qiblah while making supplication.
Making heaps of earth or pebbles: during the day of Arafat, at particular places, by some people, has no bases in the Shariah of Allah.