My opinion on surrendering to either a shelter or rescue it is only curteous to provide somesort of donation. Every darn penny helps (it truly does). If these same people had to have their animals euthanized it would cost quite a bit. If they are willing to save the dog, then the classy thing to do is give a donation.
Do shelters in your area not charge a fee either?? Shelters all charge a surrender fee here - and actually, many dogs/cats/birds are left at the doors. People don't even want to pay the 30 bucks to bring their animal into a warm building...