Gawd, I was just telling my DH today that my Dad used to have a panel van and us three kids would sit on the mattress in the back, totally unsafe - god knows what action that mattress had seen before we came along

In all seriousness though, our parents just weren't educated and obviously the technologies to create safe car seats for children/babies just weren't around. Not that thats an excuse for family to poo-poo your decision not to take the risk, unfortunately the mantra "back in my day we did it and nothing happened to us" is trotted out by the older generation way too often to justify updated guidelines/laws on things, rather than looking at the fact the new information/studies and research has been done to find a better way of doing things.