Wow, talk about a remote spot in the world ? Wow. You're talking about that little island east of the Phillipines and north of New Guinea ? Scarcely 2 x 5 miles wide ?
I see from wiki that became a territory of the USA after WWII. However, it got its own independant govt. starting in 1978. Oddly, the "entire island" is said to be on the USA's "National Register of Historic Places". Ie.: a U.S. "Historic Landmark". Which is odd, if it's now got it's own government. The status was d/t the WWII battle that was fought there.
Personally, unless there is some sort of very high-end touristy beach modern stuff going on there, I wouldn't touch the place with a 10 ft. pole. I mean, to look for historical stuff (as your post indicates when you say "history"). Because think of it: The place will be LITTERED with shrapnel, bullets, etc.... JMHO.
As for whether it's legal or not, my hunch is, that since that island became independent in 1978, that a) there is probably no laws that forbid it, and b) I bet no one would notice or care, unless you're being a nuisance in some way. There is ample detecting going on in all the Phillipine islands. So I can't figure out why this one particular island would be any different. But that's just me.
