DD is only ten weeks old so we're a while off this being an issue, but I'm genuinely curious.
Most of the parents on my social media seem to do this Elf on the Shelf shite and I just can. Not. Be. Bothered. I can get on board with Santa sneaking into the house to leave presents by ~MaGiC~, but I don't want DD thinking we have security issues with repeated breaches 
Anyway because it now seems to have become such a thing I'm a bit worried that once she gets to childcare/nursery/school she'll ask me why the elves don't come to our house. I'm shit at thinking on my feet so I need to have a response sorted to spring out when the question comes. So if you've been asked what did you tell them?