Lenser,
The cost of administering a program that keeps track of how many bags were purchased and redirects it to environmental programs is much higher than what the bag fee takes in.
The purpose of the bag fee is to reduce the amount of plastic bags that go to landfills, and that's it. What merchants do with the fee is their own prerogative. If a Loblaws sells 1,000,000 bags a year, that still amounts to $50,000 before administrative costs and the price Loblaws pays to buy the bags themselves. I wouldn't be surprised if the amount of money that finds its way into an environmental charity from selling 1,000,000 bags nets just $10,000, which is the cost of planting 3 trees or paying for half of a undergrad university scholarship. It really is chump change.