Likely story...

There are cheap excuses, and cheaper excuses, but Hong Kong is noted for cheap, as Josh Voorhees explains in Slate:

This was lost in the SCOTUS shuffle during the past two days, but it's worth revisiting: 

Hong Kong has finally shed some additional light on the paperwork mix-up that it claims was the reason officials there ultimately allowed Edward Snowden to board a flight for Russia despite the United States making it very clear they wanted the former NSA contractor arrested. According to The Associated Press:

Justice Secretary Rimsky Yuen said that Hong Kong immigration records listed Snowden’s middle name as Joseph, but the US government used the name James in some documents and referred to him only as Edward J. Snowden in others. "These three names are not exactly the same, therefore we believed that there was a need to clarify," he said. Yuen said US authorities also did not provide Snowden’s passport number.
Yuen said the confusion over Snowden’s identification and his passport were among factors that delayed an arrest. He said the government requested clarification from its counterparts in the US. “Up until the moment of Snowden’s departure, the very minute, the US Department of Justice did not reply to our request for further information. Therefore, in our legal system, there is no legal basis for the requested provisional arrest warrant,” Yuen said. In the absence of such a warrant, the “Hong Kong government has no legal basis for restricting or prohibiting Snowden leaving Hong Kong.”

(For the moment, let's set aside the obvious jokes about how the US government failed to have some rather basic information about an ex-defense contractor who himself exposed the lengths the government goes to collect information about people.)
According to the Justice Department, Hong Kong's defense doesn't exactly add up. A DoJ spokeswoman told Politico that, under the extradition agreement between Washington and Hong Kong, the US only had to provide Snowden’s description, an "indication that a surrender request will follow", a list of the crimes he is charged with and the applicable punishments, and "a description of the facts", all of which the department claims that it did.
"The fugitive’s photos and videos were widely reported through multiple news outlets," the Justice spokeswoman said. "That Hong Kong would ask for more information about his identity demonstrates that it was simply trying to create a pretext for not acting on the provisional arrest request."

Rico says that, if the slipper were on the other foot, Hong Kong would be pissed that we let someone go that they wanted arrested...