Judging from the article...
President Arthur was successful in keeping the secret of his heritage, and he died shortly after leaving the White House November 18, 1886... During the campaign of 1880, questions were asked about Chester’s birth place, but just as today, those doing the research were looking in the wrong direction... The President himself would not help matters any, he burned nearly all of his records and papers before he died in Nov. 1886, a year and a half after leaving office.
... it looks like he may indeed have agreed, based on his behavior.
-PJ
And what behavior makes you think that? What did Arthur do that's so suspicious?