How can some one forget the Visa while travelling. That too people who have travelled so many times?
I dont see any thing wrong with the mumbai immigration authority. I think they have done their duty.
Regarding the white man getting the transit Visa, You got to accept that white man rules the world.
I know so many instances where Indians are being denied entering into US in similar situation who had also been given only few hours before they were deported.
I might sound bit rude and we indians need to accept that we lack descipline.