Why are there apparent double standards ?

I read with some dismay as to the recent 2 incidents which occurred recently. One was the incident where 6 schoolgirls from an Australian international school were given a warning for shoplifting. The second was an incident whereby a passenger was abusive and hit the Singapore airlines steward. He was left off and returned home.

We have been known to be strict on misbehavior be it from painting graffitti, to shoplifting to simple acts of violence. If there is a relaxing of punishments for offences, then let it be applied evenly throughout all aspects of our civil society. 

I wonder why the authorities have decided not to implicate the 6 schoolgirls and rather, let them go back to their home country. The same could be said of the passenger who abused and hit the SQ steward.Is there a hidden hand here ? 

This harks back to the Michael Fay incident in the 90s when the Government of the day decided to lessen the caning sentence of the boy and his accomplice, when previously it was strictly enforced.

It appear that there seems to be a double standard, one for locals and one for foreign people. Or am I reading too much into these 2 unrelated incidents ?

The law and the dispensation of it should be applied equally. If there is a light touch, then it should be applied throughout all aspects of society and not just microscopically.

I am disappointed.