Is it permissible to wipe over socks during ablution without an excuse, and does the ruling differ if an excuse, such as illness, is present?

Wiping over the khuffayn (leather socks) is mutawatir (recurrently transmitted) among the people of knowledge. Authentic hadiths have been reported concerning it, indicating its permissibility absolutely, such as the hadith of Al-Mughirah ibn Shu'bah and the hadith of Safwan ibn 'Assal. However, the Malikis stipulate for its obligatory wearing the existence of a need, such as heat, cold, or rough terrain. They do not permit it for leisure or trivial reasons.