Thats their policy, but only because they want to get it over with and it will be likely you will have an epidural with that.

I had a client whose waters were broken last week, she was 2-3cms dilated when she did it. Baby born at 2pm, she kept upright and active and we did some good massage and walking to help her along.

You see you can't leave it up to them to decide for you or they will do whatever is quickest and easiest. But you are well within your right to say 'no thanks, I just want my waters broken for now, and I want to be given some time for labour to establish on it's own.'

Given that you are already 2cms and everyone is happy and healthy, I would be saying no to the drip. You will get lots of pressure for it, so you need to be strong. Get your parnter to say it if you don't feel comfortable. But can be the difference between an epidural and further intervention or not.