When Tom appears in "The Outcasts of Poker Flat," Oakhurst has "a vague idea that the situation was not fortunate." Why might Oakhurst be uneasy?

The gambler John Oakhurst recognizes that the situation
involving his outcast group is already a dire one, so when the young, "guiless" Tom
Stimson appears, Oakhurst sees that things have gone from bad to worse. Oakhurst had
previously met Tom in Sandy Bar, where he won all of Tom's money and then, in a move
that displayed Oakhurst's genuine humanity, he returned the boy's money. Stimson became
eternally grateful and one wonders if the boy had followed Oakhurst or whether their
meeting was just a coincidence. When young Piney Woods appeared, a girl of but fifteen,
Oakhurst must have seen that his situation worsened still. Tom was a giggling youth who
seemed happy to have met up with the party, and he did not recognize the situation the
group was in. Oakhurst saw the signs in the sky of bad weather, and to him, Tom may have
been still another sign of the bad luck that had struck him.