The U.K.'s Advertising Standards Authority banned the above ad for Dior mascara starring Natalie Portman after competing brand L'Oreal complained that it mislead consumers about what the product could achieve. Dior admitted that the ad was retouched to "separate/increase the length and curve of a number of her lashes and to replace/fill a number of missing or damaged lashes, for a more stylised, uniform and tidy effect." (As though L'Oreal doesn't use similar techniques for its mascara ads, but DETAILS).
I interviewed a retoucher not long ago about the work, and this person explained that mascara ads — by all brands — are the worst when it comes to retouching:
