When I returned from US after short visit and landed in 2008 at Mumbai, to my surprise large number of custom dept. employess(not sure if they were officers) approached me one by one. All of them were asking for $20, give $20 and will pass your luggage.

I am glad i said no to all of them and to last one I said ... give me $20, I'll show you how luggage passes screening if you don't have anything to declare.