I wanted to add one thing: Ruth is breastfed and I've no issue feeding her in public. In Maryland the law (Md. Health-General Code Ann. § 20-801) permits a woman to breastfeed her infant in any public or private place where she and the infant are allowed to be and prohibits anyone from restricting or limiting this right.
Thus far, I've fed her at a community association get-together, on our back and front porches, local park, and a local cafe. Maybe it is just me but I think most people prefer a quiet, breastfeeding infant to one Oh, and in the doctor's office. Coincidentally, the pediatrician's office was the only place I've had a problem -- not from the pediatrician, of course, but from a parent who "didn't want [her] sons to see that." Yes, I was very surprised too. Yes, the staff informed the parent that no only was I within my rights but that the practice encouraged moms to breastfeed where they were comfortable.
If Ruth woke up on the MARC train, I'd have popped her right on. But she work up as we were waiting for the F6 bus. She has a good latch but the thought of trying to hold her as the bus bumped along from New Carrollton to College Park made me nervous -- metro bus drivers are not known for smooth transit.