Catching Fairies

So Miranda has it in her mind that she is going to catch a fairy.  Some friend at school told her how to do it and so she got a little container, made a little fairy bed, put some fairy food in there and then puts it near her bed. Each morning she is surprised there is no fairy in there.

Today she asks me if I can call Sophie, who apparently caught three fairies, and ask her if Miranda can have one. I tell her that no, I'm not going to do that, but that she can ask her tomorrow at school.  Then this conversation happens.

Me: Miranda, why do you think that the fairy will just stay in your container? Why can't she just fly out the way she flew in.

Miranda: Well, she comes at midnight, sees the bed, thinks it's cozy and falls asleep. Then I wake up in the morning and close up the lid.

Me: Oh.

Elizabeth: That won't work because fairies are nocturnal.