How untruthful do you think advertisements can be?

No limits and to any extent if the receiver is ill informed.

Between30 and60 %, and it's based on visual illusions and developed brainwashing tactics.                      Thank You. 

I agree with the experts answers. Thank you.

Advertisements and any form of marketing must be truthful and realistic. Obviously you can speak up the characteristic but the data and the facts have to be available. Advertisement is a highlight. 

1.Offering the customers

2.Discounts in price

3.Quality will be different in product

i think it should not cross the line drawn before emotional threshold of changing mindset. 

Unfortunately, advertisement has become the tool where lies start.

I think all the advertisement doesn't saw100% real picture of the product. There may be some of the untruthful in the advertisement, but the way of advertisement people come to know about the product and company and after consuming product once, he or she can see real test of the product so advertisement doing good work in market.

Gone are days when advertisers can be untruthful. Of course you can still be untruthful advertising your product and services, and you can go to any extend, but the more untruthful is your advertisement campaign/information, more damage your advertising will cause to your product and services,

Companies in todays world do market research, A/Y testing of data to make sure that marketing campaign and advertising can have long lasting impact on mind of target audiences. 

I believe that buffing in media will come back with bad effects because raising the customer expectations to limits that your product cant reach will defiantly damage your reputation sooner or later.