Stripping or sweeping of the membranes is something often performed during a vaginal exam at the end of pregnancy, with or without prior knowledge of the pregnant woman. During the vaginal exam, the midwife or doctor places a finger inside the opening of the cervix and separates the membrane (or amniotic sac) from the uterus. The goal is not to break the water but to simply "stir things up."
The down side to stripping the membranes is that it can be quite uncomfortable while it is being done. Many women also report that it leaves them with some spotting or bleeding. Others also report feeling achy or having irregular contractions after the procedure.
The Cochrane Database says that doing this will help reduce the number of inductions for over due pregnancies. Though eight women will have to undergo the stripping of the membranes in order to avoid one full blown induction.
It is certainly worth discussing this matter with your practitioner at the end of your pregnancy to see if it would be beneficial to you. The good news is that there were no differences in maternal or fetal infection rates.
Boulvain M, Stan C, Irion O. Membrane sweeping for induction of labour. Cochrane Database of Systematic Reviews 2010, Issue 1. Art. No.: CD000451. DOI: 10.1002/14651858.CD000451.pub2