This sign at the Koh Sumai airport is funny. It warns you to be suspicious of foreigners who are thieves but they are not saying so in so many words!
This is another sign at the airport and instead of a set of simple instructions they have chosen to ask you questions!
There is nothing funny about this notice board except that it looks like an informal notice board of a school instead of any airport. Cute.
More humorous signboards: Funny English Signs (for wrong English) or Funny Road Signs in India or Interesting signs with funny instructions! Happy Birthday Political Posters or Thieves beware signs from the UK