"Abe" wrote in message
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.

Everyone is responding like he did get scammed, but I'm not so sure.

He was scammed. This trick has been around for years. Quote a low price,
start the job, then demand more money. No different than buying a gallon of
mild at the grocery store and on the way out being asked to pay more. If
you are that naive, please don't make any big decisions on your own.