So far in three labors/births ive had one ve and it was at my insistence in my first labor at 8cm. I think I was actually entering transition as I suddenly decided I wasn't in labor at all and needed reassuring I was and it was real. I dont remember it being painful or anything as it was on my terms and I was prepared I guess.
I have "no ve's unless requested by me" in my birth plan in big red letters.