The Kingdom of Hawaii was an internationally recognized sovereign and neutral state. Russia, Great Britain, France, as well as the US to name a few had formal treaties with Hawaii. Prior to the US, there were incidences where Hawaii had been temporarily taken over, but in each case was able to regain her sovereignty. For the record, it was only the US who illegally annexed Hawaii in 1898. Would some other power occupy Hawaii, if the US returned control of Hawaii to its rightful populace, would be pure speculation.
Your statement is purely speculative. Yes, if we were in the 20th century or before, it was customary for the major powers of the planet to colonize and/or vassal state smaller sovereign nations. However, in the 21st century, other than the American regime change debacles in the Middle East, there has been no such activity to date.
Kuleana
A free trade agreement is not a peace or non-aggression pact. Almost every country an imperial power conquers starts off with normal trade. Then they realize, "Hey, wait a second, we can just take this stuff!" and they do. I'm sorry, but you seem to be under the false impression that the world is fair and peaceful. "No Gun Zone" signs don't work, nor does simply declaring sovereignty without the means to back it up. Besides, what's to say Hawaii wouldn't have almost immediately regressed to island vs. island warfare? Besides, what the "Sovereign Hawaii" people don't want to ever talk about is that Kamehameha got in bed with the Americans for their arms and technologies- the arms he used to conquer the other islands. If it weren't for the Americans, Hawaii would have never been unified in the first place. All in all, no matter how you look at it, Hawaii was simply too primitive while being too strategically and resourcefully important.
As for London808 being speculative, no, in the 21st century: plenty of native peoples have been displaced in S. America, Russia has annexed Crimea, China
would have taken over a lot of the S. China sea if it weren't for the U.S., Pakistan and India still are fighting over Kashmir, Turkey and others continue to occupy Kurdish territory, etc. Besides, if colonization stopped, it wasn't for any moral reasons, it was simply because there was no more worthwhile territory to be had.