I had a c section so I let the midwives use dispos for the first day. As soon as I was up and about he was in cloth and wool. The midwives were very impressed with my cute little Muttaqins and cotton tots and loved his longies!
I don't see that they can stop you taking cloth - out hospital insists you provide nappies (though they put his first one on in Theatre, it was a Moltex!) and if you refuse to buy/supply dispos, what are they going to do, exactly?