Could they have been there for no other reason than to get rid of unwelcome visitors?

If I have unwelcome visitors, that's usually where they come from.

An office word entered his head and stayed there like an unwelcome visitor from out of town.

Only then did he turn to face his unwelcome visitors.

Then our country will be rid of all its unwelcome visitors.

Trouble first arrived a few weeks later, in the form of some unwelcome visitors from the tube station.

Q had been an unwelcome visitor before, and she didn't want him around again.

Lauren looked around at the world where she had been dropped, feeling like an unwelcome visitor.

The unwelcome visitors advanced into the middle of the room.

"We have had some unwelcome visitors" was all he would say.