I've heard of this very sad situation too.
Especially in Las Vegas where my son lives. I think L.Vegas has some of the the most Foreclosed Houses in the nation. I read on the local website there that they are always finding pets that have just been left in the house to fend for themselves when the owners are forced to leave.
I too would keep my dogs under any circumstances. They are members of our family. I'd eat less, share the food with them or buy them cheap dog food just till I got back on my feet. I don't know how anyone.....could do this to their "pet".