If you find a character not carrying a yellow bag, this from the new RoE applies:
"8. All players must carry a yellow bag in which items available for looting or stealing must be kept. In addition to one or more items from this bag, food, drink, gems, and up to 1000 gold coins may be taken per victim."
So the yellow bag is merely a way of letting "other" things get stolen as well.
The RoE can be found for reference here:
http://roe.moongates.org/