If you're going to displace civilians by force and under penalty of death, it is then your responsibility for their safety, feeding, and shelter. Neither the Portuguese government nor Wellington took little or any responsibility for that displacement.

Napoleon was urged to do the same thing in Saxony in 1813 but refused.

You could always get hold of a copy of the book and research it yourself. Jones and Dickson are listed in the footnote for one of the passages on the subject in the author's book.