Re: What does the top tether do?
The debate centers around potential neck loads with a RF tethered seat. I personally (THIS IS MY OPINION just to make that clear) would not RF tether a seat for a newborn. The idea is that the tethered seat would cause greater neck loads that could be too much for a noob. The energy would transfer more to the baby than being absorbed in the the rebounding motion. My 2.5 year old's seat is RF tetherd (Radian) but in a situation where I feel rebound would be a bad idea for a newborn (truck with low seat back and nothing between glass and baby) I would opt for a seat with an anti-rebound bar.
CPST-I and SAHM to DS