Dear Nina,

> The Visuddhimagga explains that only ariyans are successful
> in the Recollection of the Triple Gem,

In ~Naa.namoli's translation this is actually claimed of all
the first six anussatis. I believe, however, that there is
an error here. The Pali reads:
imaa pana cha anussatiyo ariyasaavakaana~n~n' eva ijjhanti.

~Naa.namoli translates:
"These six recollections succeed only in noble disciples."

But if we allow this translation, then a few paragraphs
later it appears that Buddhaghosa is contradicting himself,
for he states that a suitably qualified puthujjana may also
enjoy success in these practices:

eva.m santepi parisuddhasiilaadigu.nasamannaagatena
puthujjanenaapi manasi kaatabbaa. anussavavasenaapi hi
buddhaadiina.m gu.ne anussarato citta.m pasiidatiyeva.
yassaanubhaavena niivara.naani vikkhambhetvaa
u.laarapaamojjo vipassana.m aarabhitvaa arahatta.myeva
sacchikareyya ka.taandhakaaravaasii phussadevatthero viya.

"Still, though this is so, they [the anussatis] can be
brought to mind by a worldling too, if he possesses the
special qualities of purified virtue, and the rest. For when
he is recollecting the special qualities of the Buddha,
etc., even only according to hearsay, his consciousness
settles down, by virtue of which the hindrances are
suppressed. In his supreme gladness he initiates insight,
and he attains to arahantship, like the Elder Phussadeva who
dwelt at Ka.taandhakaara."

I suggest it would be better to follow Dhammapaala's reading
in the Visuddhimagga-.tiikaa, in which the particle 'eva' in
'ariyasaavakaana~n~neva' is read as an
uttarapadaavadhaara.na, that is, a limiting particle that
belongs to the word that follows (ijjhanti):

_ariyasaavakaana~n~neva ijjhantii_ ti ariyasaavakaana.m
ijjhantiyevaati uttarapadaavadhaara.na.m da.t.thabba.m

And so the translation ought to be something like:
"In noble disciples these six recollections can only
succeed." [i.e., they can't fail]

Best wishes,
Dhammanando Bhikkhu