A safe box??

Meggie is indoors and when I am not there she is shut in her cage with a play pen attached.
She has some toys, some wood to chew and a carrier with the door taken off.
When I shut the play pen to leave she goes in the carrier, when I get home from work she is in the carrier.
When I am at home and she is free range she doesn't go far from her area but doesn't sit in the carrier, when I am in bed she is shut in cage/play pen but doesn't go in the carrier that I can see.

Why is this? I am concerned that she sits in the carrier all day, but have no way of finding out

maybe it's just her favourite resting place?

Carlton goes in his crate overnight and he goes straight in his cardboard bedroom and pretty much stays there until ryan gets up - he pops out for hay and water but he prefers to chill out.