Why is 'corkage' sometimes so expensive at BYO restaurants when it's just opening/pouring a bottle of wine?

Question

Why is 'corkage' sometimes so expensive at BYO restaurants when it's just opening/pouring a bottle of wine?

Answer 1

Because its not just about the fact that they are openning the bottle for you, they need to make up for the beverage you would have purchased had you not brought your own.

Answer 2

Corkage is a way to make more money.  They need to make sure meals are not too much over the average price, so they find other ways to get more from patrons.

If I wasn't drinking my BYO I would drink water, so they wouldn't be getting anything less out of me!