I would personally be a little worried about them not sterilising in a hospital..... there are so many germs in hospitals that you or baby would normally not be used to, thats why they get out breaks of super bugs and stuff every now and then and also why they usually go to great lengths making sure everything coming into contact with patients is serilised like bed sheets, towels etc.. why should bottles be different?

On the other hand at home you will have built and immunity to the bugs in your own home since you live there and as such will have passed on the same immunity to baby during pregnancy.

I've been told by the child and youth health midwife to sterilise until they're about 4 months old because their immune and digestive systems are still immature at first, then after that its good to start letting the germs in to build up their immune system, but like i said just to wait for it to be fully developed first.