Travel can be a pain for women because there are enough idiots in the world who will take the opportunity of a woman seated next to them to make them miserable for the entire flight by making unwelcome advances etc. IndiGo recently launched a program to try to address this issue. If the ticket is being booked for a female passenger then the system will show them the seats that are already occupied by women. This allows the passenger to book a seat that is next to a lady passenger. I first noticed this when I was checking in Jani for her flight. The below screenshot shows what it looks like:

Female Friendly seat selection option
I think this is a good move but as with all things there is an easy way to game the system so men can ensure they are seated next to a lady. Basically, I need to open two windows. In one window I would search for a flight ticket pretending to be a lady passenger. Since the payment is not required till after we do a seat selection I get to see which seats are occupied by women. Then I cancel the process and start a fresh one with the actual passenger details picking a seat next to a lady.
There is no easy way to detect and block this. One option would be to allow the seat selection only after making the payment for the ticket but that would mean folks would have to make a second payment for the seat selection as most of the options are paid ones, which would not be a user friendly experience.
Even with that, this is a good move and should help make the flights more comfortable for women.
Source: NDTV: IndiGo Launches Female-Friendly Seat Selection Option. Here’s What It Means
– Suramya