Agree in general with you that lying is big No in interview process.

However, asking salary is a very delicate question that they are not supposed to ask. Making such question a mandatory to get offer is a very shady and questionable practice. I have no problem in telling employer my Desired Salary number (that I know they can pay) as my Current Salary is just another negotiation trick. The ultimate goal is to get both parties to agree and make a deal. By volunteering your true salary you are just giving up your negotiation edge