I beg to differ on the spine issue. A capsule holds a baby in the supine position, which has little impact on a 0-6 month old babies spine. (I have researched this extensively, as all my babies have sleot in a hammock from birth to at least 10 months, which holds a baby in a very similar position to a capsule).

In terms of leaving a baby to sleep in a capsule, again, I have no issue with this. Olivia was born in the Territory and as such did a huge amount of sleeping in the car capsule as we travelled very long distances. Hours on end. As such, IMHO, leaving a baby in the capsule to nap over a coffee at a friends place is a lot shorter in duration, so I have no problem with it at all. Each to theri own, of course.

My preference is to hire a capsule till they hit 9kg & have good head control, then move to a front facing car seat.

HTH