Switch default buttons in warning message

I don't think it's a good idea.
All yes-no message boxes have their yes button on the left, and their no button on their right.
People are used to it, and I think changing it will be only confusing.

People are used to it? How often do people see messages like that to become used to it? Must be blind robots. Actually yes, you make sense, a person with working eyes and reading capability wouldn't have any trouble with PUPs at all. Only blind robots do.
Hmm, but since these robots are blind, what about the possibility of them misreading "not recommended" and taking it as "recommended"? Would putting that word next to "No" break the robots too?

The problem may also be that when they see the message, they'll automatically click on the "longer sentence" instead of No.

Well, you can't help a person who can't help him/herself.