I had the $5 in my pocket, but used it at JNB for the baggage weight police at the security entrance to let me through with my carry-ons...8kg is really quite light when you consider people carrying laptops/chargers/cameras/etc. Those overheads were built to handle it.

I simply ignored all the people in DLA that volunteered to "walk me through" security and to the lounge. Beware, they will have their hands out in no time!