In America you can also do that, but how far you'll get is highly reliant on the mentality of the manager that has to do a price override.

For the most part, when it's happened to me, they've always taken the loss on the chin and then the next time I come in the prices have been updated, but I have also once encountered a grouchy old bastard manager who, when I asked to pay the price that was listed on the shelf, immediately launched into a tirade about how people are so ungrateful and how he's not making any money, blah blah blah.

I immediately put my intended purchases on the counter and left while he berated me the entire time I was walking out of the store.

But, crazy people aside, if you're not a dick about it then most of the time they'll do right by you.