Indeed the captain of the Impeccable did carry out his duties and stopped, and he stopped quite in advance of any collision. This shows that while stopping infront of the Impeccable did create problems, it is still far from being a hazard when stopped considerably far away, as the photographs a few pages before have shown.
The fact that the Impeccable had to stop to avoid a collission proves two very important points.
1st, free passage was impeded and halted. This is illetgal in an EEZ for anything not associated with natural resources, marine sciences, or environmental violations.
2nd, the fact that one ship was able to stop does not mean that there was not a navigation hazard. In fact, it tends to prove that there was one created by the other party because the captain of the Impeccable had to stop to avoid it. He wasn't stopping to avoid any natureal hazard or threat, rather to avoid one directly placed there by the other vessel.
Again, it may be in the power of the PRC to impeded, hazard, stop, board, etc. any vessel in that zone.
That does not make it legal.
There are very specific and restricted instances where it would be legal and the Impeccable was not involved in any of those.
We all know what the real issue here is on both sides.
Let's hope that it cools down now and that the tension lessens. I expect that both the PRC and the US will continue to use whatever means they can to observe the technology and platforms of the other.
As long as they remain outside of territorial waters, as long as they do not violate interntaional provisions, and as long as they do not overtly threaten one another...that is normal.
I also expect that both sides will try and use rational means to prevent this on both sides...again, the same criteria applies in terms of that provision.
I view this incident, as much as anything else, as both the PRC and the US coming to terms with these realities as the PRC grows in its major power status.