From the bail hearing:

Prosecutors told a Las Vegas court on Friday that Mr
Hutchins had been caught in a sting operation when
undercover officers bought the code. They claimed the
software was sold for $2,000 in digital currency in
June 2015. [1]

So he was caught in a sting involving beer money at age 21. As the parent of a young man who recently managed to puncture a hole in the gas tank of a Buick without a clear explanation, my general take is that like many if not most young men, Hutchins has done one or more stupid things prior to the full onset of adulthood (not to suggest that the full onset of adulthood is necessarily entirely effective).

Hutchins could have been arrested any time between June of 2015 and August of 2017. This includes:

1. Arrest in the UK. However, this would have required extradition and the expenditure of diplomatic capital given the relatively insubstantial ill gotten gains Hutchins is alleged to have received. The quid pro quo for $2000 in potentially illicit sales would expose a lot of very average people for a lot of very trifling offenses on both sides of the Atlantic.

2. Arrest when Hutchins first entered the US in association with Defcon. He could have been picked up at the airport upon arrival. Arrest in the US at the first opportunity seems the ordinary first alternative to extradition.

3. Arrest while Defcon was going on. Prosecutors argued at the bail hearing the Hutchins was a flight risk. Yet he was allowed to get all the way to the gate for his flight before he was detained.

Ok, extradition is a mess. But picking him up earliest opportunity is pretty standard. Waiting until he is about to board a flight suggests either ineptitude or surveillance or the grand jury passing down an indictment during Defcon. I don't really buy ineptitude due to it requiring multiple Federal agencies falling down in routine police work.

In a surveillance scenario, publicly arresting Hutchins puts any and all other targets of surveillance on notice. Without other arrests, that seems rather inept policing.

Late execution of the warrant suggests a high level agenda to prevent him from being arrested (or questioned) in the UK or detained at the port of entry in the normal manner. Another possibility is the grand jury did not issue a indictment until just prior to Hutchins arrest. This points to a high level agenda as well since presenting evidence to the grand jury between the time Hutchins arrived and attempted to depart would involve significant logistical effort...on a two year old sting operation.

To the degree that Hutchins is an attractive intelligence asset, a high level agenda is not implausible. Digging up a skeleton from his closet is not extraordinary spycraft. Letting him get to the airport before the arrest catches him at his most vulnerable and the transition from vacationing Los Vegas luxury to a concrete and stainless Clarke County jail cell is not going to strengthen most people's will.

Of course, I am just speculating. But the fundamental premise is that the people of the state level intelligence communities tend to be professionals and good at what they do.

[1]: http://www.bbc.com/news/technology-40833951