They do indeed still do this. They also do the same thing twice a year on NPR (National Public Radio).
PBS does receive government funding through taxes and the past conservative regime has tried a few times to cut/eliminate funding for PBS. :(
I seem to recall occasions when the American public channel (pbs?),
which had most of the best TV (IMHO), would raise subscription money by
interrupting the program until their viewer's pledges reached some
threshold. During this break, some PBS people would wheedle ('Please
please please, pledge, then you can get back to Dr. Who/ Nova/ etc.
sooner... And support all that other stuff you like to watch ... ). Do
they not do that any more? I've been here for nearly 10 years so things
may have changed.
Ora, lege, lege, lege, relege, labora et invenies.