Buying the hiker’s silence
If anyone learned how these tiger cubs came to be at the zoo, they would most likely be returned to the nation from whence they originated, and the owner of the zoo wanted to do all in his power to prevent this from occurring. The trekkers were forced to make a choice as a result. However, they did get the impression that choice had already been made for them.
No other choice
If they decided not to go through with the arrangement, the animal shelter would also be deprived of the funds that they so sorely required. They all agreed to take the bribe, and as a result, the owner of the zoo was able to get his three new animals. But, thank goodness, this was not one of those facilities with cramped cages where animals are kept for the purpose of being used.