Comment by mind_heist

Hmm.. You are right though. Here is an implicit Premise that this works on & and its not being declared verbally.

- "The way airports works in these destinations" - Customs officials don't stop and question everybody ; in most cases - if you are dressed well and speak respectfully , they let you go.

- I have heard Mumbai and Bangalore Customs officials could be unyielding at times ; they stick to the rule book and levy all taxes if caught . Not the case for other airports in India ;

- I m not sure about airports in Bangladesh ; Thailand ; Nepal ; Sri Lanka ; Malaysia and Indonesia - I guess the founders do have a certain insight into how these airports work.