Worth considering what it looks like though! A shipping container might not look great -and if all woodland owners put one in their woods, this would perhaps upset many people and as a result they law might get changed and made more difficult for us.
Not meaning to put a dampener on it, but worth remembering that what each owner does can have an effect on us all at some point. Not sure what the answers are though... allowing nice little wooden sheds would be a start I guess!