Though I have had guests (uninvited) at awkward times, normally, people call first. On the rare occasion they don't call first, I never tell them to get lost. If I'm super busy, I simply let them know & they come back later/another day. Otherwise - if I'm not super busy - I do invite them in & roll out the red carpet.
RE: Uninvited Guests - and Unwanted too...
Though I have had guests (uninvited) at awkward times, normally, people call first. On the rare occasion they don't call first, I never tell them to get lost. If I'm super busy, I simply let them know & they come back later/another day. Otherwise - if I'm not super busy - I do invite them in & roll out the red carpet.