doubled fried chips from chip shops

[ging84]

Went to a chip shop today, something i rarely do, because i'm not a fan of soggy chips pale chips which is usually what you get.
As i was getting my order another person was making his order, and he asked for his chips to be double fried, and they seemed happy to oblige him and they didn't seem to be charging him extra or anything.
I've never come across them doing this before, so i am wondering is this a thing that most chips shops do, or perhaps just something peculiar to some of them? Is it a new thing or something places have always done?