It happened yesterday. A truck cruised in our neighborhood and I saw
them stop by our neighbor's house (we have a concrete driveway, his is
asphalt) and they talked. Then I went to do something else, the next
thing I know is that my neighbor's asphalt driveway was sprayed with
some tar like substance. So I went to talk to see what happened.

He said that he was scammed: they first agreed on a certain price
($175), they took the money, sprayed half of his driveway, then acted
all surprised and said that "it takes a lot more coating than they
expected" and demanded $50 more for finishing the work. I guess with
the implication that if he did not pay, they would drive off with his
driveway half sprayed looking really stupid. So, he said he paid extra
$50 and they finished the work.

So. I am aware that the general wisdom says do not give work to any
"drive by" people. But I would like to know, let's say that due to
poor judgment, it happened to me and these artists demand extra $50 to
finish. What would be a sensible thing to do in these lousy
circumstances?

i