It is prudent to be suspicious of anything from Bayside.
But this handwriting analysis does make me suspicious of the alleged "Third Secret."
http://www.tldm.org/news/lucys_writing.htm
I suspect they're correct about there being forgery involved. But I would not agree with most of the conclusions they draw from that theory.
Possibly the Vatican's forger copied out a portion of some statement by Sister Lucia, because her complete statement contained things they did not wish to publish.
At any rate: 1) people who had said they had read the Third Secret or had examined the unopened envelope agreed that it was written on one page, not three pages, 2) the handwriting on the three pages does not resemble known samples of Sister Lucia's handwriting, and 3) Cardinal Ratzinger's so-called "commentary" on the alleged "Third Secret" deliberately tried to minimize or even discredit the importance of Our Lady's apparition at Fatima.