Hi Lulu,
It is common for women to feel the urge to push prior to being fully dialted, however it's not necessary to do a VE to determine this. There are several 'fully' signs that we look for and in the absence of these signs some midwives will (for lack of a better term) 'let' you have a push and observe what happens. If there are no signs of descent most midwives will encourage women to try not to push and breathe through it as pushing on an undilated cervix can cause swelling and therefore prolong the labour. Some midwives will offer the woman a VE as sometimes the woman wants to know where she's at. Believe it or not most midwives don't come to work with the aim of doing as many VE's as possible, more the opposite. We will only do it at the womans request or if there is an indication.