There is a small bug in varrock, so please be careful. It is possible to get stuck behind a fence in the south-east corner near the 'dancing donkey' inn. Please do NOT go there or you may become trapped.
If you are already trapped then it is possible to escape by clicking 'attack' on an npc on the opposite side of the fence, or by clicking 'follow' on a player on the opposite side of the fence. If you still can't get out then wait until monday when the builders are coming in to remove that fence.