I had it as I was hoping to homebirth through my hospital middy and its part of their policy for their homebirths. I was positive so had to go in, I did labour at home for 8 hours first though as my waters hadnt broken. I went in and had the antibiotics but only one lot as they are every 4 hours and I was only at hosp for 3.5 before DD was born. The hosp checked her temp regularly afterwards too and did make me stay on 24 hrs though. I think you would be fine to decline and just monitor following birth.