What is considered as being prevented (ihsar) in Hajj?

Hazrat Ibn Abbas (may Allah be pleased with them both) states that nothing except being stopped by the enemy will be considered as "ihsar" (prevention), and Hazrat Tawus says that in this day and age, there is no "ihsar" at all.

Hazrat Ata says: Ihsar (being prevented) will not be counted except for the person who is afflicted by illness, or is stopped by an enemy, or is prevented by some other matter.

Hazrat Ibn Umar (may Allah be pleased with both of them) says: Only the one whom the enemy prevents will be considered as Muhsar.

Hazrat Urwah says that anything due to which a pilgrim is prevented from traveling will be counted as "ihsar" (prevention).

Imam Zuhri says that the one who halts during battle will be considered as "Muhsar" (one who is prevented).

Hazrat Ibn Zubair says that the form of Umrah in Hajj Tamattu’ is that a person puts on the Ihram for Hajj, then some illness, enemy, or some other matter prevents him from performing Hajj.