I am in the same predicament. We bought a Safe n sound capsule and DH put it in the car, following all the directions and it still moves from side to side very easily. I don't feel comforatable putting my baby is that at all.

Im not sure how the NRMA/RTA/RAC etc would make it any sturdier as there are only 2 belts, the one it comes with that attaches to the back window hook and the middle belt which goes through the capsule.

I just don't like the idea and im feeling very nervous.