You also have the right to order them out of, or deny them entry into, your house. They can come in with a warrant of course but there are situations where they don't have to have one.
Many of us follow our instincts here. Similar to the scenarios above, we give as much space as possible in an effort to avoid adding to the danger and possible trauma of the situation.
Although now that I think about it, I never knew what the specific procedure should be, according to local authorities.