I guess this is less a aibu and more I should/ are there real risks?
Thinking that surely lots of people do and their kids don't have massive spinal defects?
I would be doing it out if desperate need rather than just to be defiant! I am expecting twins and have dc2 will only be 18months when they arrive, I've seen that you can actually fit 3 seats on select but seats are for 6 months plus.
Would you risk it? If I don't I fear I may never leave the house Aline and though there are other options such as Abc adventure that take 3 little ones, we just don't have the £900+ it costs.