Strange recycling people

In our town, every trash day people come by on foot pushing a little
cart and dig through our recycling bins. They pull out all the items
that have deposits, as well as glass bottles that can't be returned in
our state. Sometimes, when we've yet to get up and get the trash down
to the curb, they will even be brash enough to go up on to our porch
and pull out our bottles.

My original thought was that these were poor people trying to make a
buck (if this is the case, I'd probably be a sucker and feel sorry
enough to leave them a few $ or something at xmas), but now I'm not so
sure. Seems like too much effort for minimal reward, and also what do
they do with all the glass? Transport it across state lines?

My second wild thought was that they were actually employed by the
town to handle this type of recycling (it seems we have several
different types of trash services for each type of trash), but it just
seems odd that a relatively wealthy town would hire people on foot to
do this sort of thing.

Just curious if this is a common occurence anywhere else, and if
anyone can shed any light on this practice.

Puzzled,
jen

P.s., I have tried to ask these folks, but none of them speak english.
They seem nice enough and don't act cagey about what they're doing.