For many developing world women, reproductive control is a difficult thing. Men have control in households and taking a pill each day might not fly. As these women are aware of the impacts of having many children, they are desperate for a way to control their lives and the lives of their children. Under such circumstance, I can see two things possibly happening:
1. The woman take the shot because they know they do not need another child, at least not so close to another birth, and their husband will not go along with daily pills.
2. The women feign ignorance when asked during what would become a public investigation, to excuse their actions from their husbands.
Now, maybe Israel did sterilize immigrants out of racism and state purity, but the above explanation has at least as much chance of being the driving force.