"According to Alfred Patterson, the hare tongi were built on [the island of] Hare as places for people to hide from spirits (aitu) which came in from the sea. 

E hakamuni ni aitu takapo tai means 'to hide from spirit groups from the sea'. 

The idea evidently was that people could be seen in normal houses with open sides, whereas they could not be seen by the spirits when the roof came down to the ground. 

At [the island of] Touhou, according to Patterson, the people could be protected from the spirits by the ariki priest who resided there but at Hare they had no such protection. 

He also stated that the aitu came in from the sea during the middle part of the day, about 11 a.m. to 2 p.m. 

Hence, women working in the puraka cultivations in the outer islands took care to return to Touhou before the dangerous period started."

(Kapingamarangi)