I think the technique predates "Backpacker". I've got one book that discusses the method, Roughing It Easy by Dian Thomas. The paperback is dated 1974 whereas "Backpacker" started in the spring of 1973. Given delays in writing, editing, publishing, etc, and especially given that I'm sure the author of my book didn't develop the idea, I think the idea was floating around well before "Backpacker".

Either way, it is an old, old 'trick.'

FB