Then your snake knows what he needI have noticed that from time to time my boy will do the same for up to a week, nothing to worry about.
This is true, but I stopped using this option last year as I noticed that once my bp was given a mouse instead of a rat, I would have refusals to rats on and off for a few months. Really it depends on how picky your snake is but I go with 2 smaller rats when what I need is not available.