I bring bottles to daycare- but they also keep a few bags in the freezer in case she is extra hungry one day.
I have to admit though that I have been carrying a 2 oz sample bottle of pre-mixed formula in my diaper bag since we left the hospital for "Just in case." Seems pretty silly now since she's never had formula and I could BF her if I need to. I just realized that that case of formula expires in June and I should donate it to the local women's shelter before it goes bad. I have to admit that it did make me feel better going out and about at the beginning to have it there. After nearly 4 months of successful BFing I guess I can let go of my 2 oz of formula