Dan - I was wondering the same thing. Found the following in anotehr post on another site... It's just something to remind yourself if a particular battery is "charged" or "discharged". If you had several batteries in your bag, some charged and some discharged, there would be no way to quickly tell them apart. So you would manually flip the (fake) switch to either have the red dot showing or not. For my use, I decided that red dot showing means it is charged.