Why is it not permissible for women to attend walimahs.

Answer

Just as it is not permissible for women to attend the Musjid even if there are separate entrances, so too is it forbidden for women to attend 'walimahs' nowadays. Furthermore, the 'walimahs' nowadays are farcical and bid'ah. In fact, it is not permissible for even men to attend the reception organized by the girl's parents on the day of the Nikah. Such a reception is not the walimah. Women used to attend the Musjid for Salaat during the age of Rasulullah (Sallallahu alayhi wasallam). However, this was unanimously banned later by the Sahaabah. The same applies to walimahs and to all other merrymaking functions.