Have to agree with you on this one Erin.  Back in the day that soil/sand was easy to dig in, so that would be a likely place for burials.  In addition, there is no reason to believe that those are necessarily Polynesian-Hawaiian bones.  There was a huge Asian culture in Hawaii, after 1880, that actually out numbered the Polynesian-Hawaiians for a while. In addition of course to Portuguese, Filipino, Europeans, etc.  They also died and were buried. So, this assumption that every bone found "must be" Polynesian is silly without DNA testing, which is costly. 
Since no one knows who these folks were they should be relocated to a more appropriate place.