I make it a point, where ever I am, not to "hang around". If wife or I or kids need to go to the toilet, we do that after getting off the plane OR after customs. I make it a point to always purposefully walk to a inspection point (immi/cust) in long strides. Gives the impression of "he knows the deal". I've never been stopped apart from when I was 17 years old at CGK and didn't have an onwards ticket (which I was going to buy in Jakarta).
More often the ones I see who get stopped are those who seem "easy prey" as they look unsure or loiter around.