Surely they then become a problem which they can solve. Most of the time they realise this so do not actually show themselves. That's why it is hard to see them
Mild, Misty and drizzle up here. Very unseasonable. Our house is currently where Santa has stored our grandkids pressies, so once they are safely tucked up in bed I get on the sleigh, disguised as a Vauxhall Astra, and do the deliveries making sure the mince pies and carrots left out are consumed.