In the August 1970 issue of the NZ Beekeeper magazine, an article by
Keith Doull, et. al., describes the use of "Plastic Bags to Hold
Maintenance or Stimulative Food in Beehives".
 
Important points in their use include making sure there is no
pockets of air sealed in the bag, putting the punctures in the top of
the bag only, and increasing the speed of uptake by putting more
punctures rather than larger ones.
 
The main advantage was seen as the ability to vary and control the
rate at which bees receive the food.
 
The method was developed in the summer of 1964-65 as a method of
feeding bees in lucerne pollination cages.  It had become standard
practice for some beekeepers in South Australia.