Not killed outright, But uuummmm yeah, common sense says they wouldn't have lasted too long.
They were weak & sick and tossed out into a strange wilderness, It's not like they could go to the nearest Caananite social services department and get on welfare/medicaid. They most certainly died of starvation or exposer or were eaten by wild animals within days.
I don't understand the arguement, Yeah I guess in most cases (though probably not this one because they probably would have died horribly over time) being exiled is better than being outright killed, But it's still not exactly a good thing.
Instead of your own predilection (misrepresented by the way as "common sense") why don't you go ask the people you have have carried that story along in far more detail, preserving it for generation after generation. In other words do some research -- ask the experts. Why suffer a burden of misunderstanding when you might -- in true scientific researcher fashion -- resolve the issue. Certainly it would add to your understanding, and who wouldn't look to add to accurate understandings?