hi!
No,it is not so,it cannot be a diplomatic way of telling a lie.Today huge investments go in building a brand and promoting it thru advertisements.ads are means to imbibe ur product in the minds of the customer. the consumer today is too intekkigent to differentiate between a lie and a genuine product. many a times the value of the product is disgused as a status symbol,hence we may feel that it is not worth the price,but actually the price is for the status symbol u get and not solely the product.hence,advertisements can never be consiered as diplomatic lies.