Having a daughter that works in advertising, I guarantee you most of the time this is not true. At her previous employer, before she started to work for the ASA, she was forever sending back clients copy for all manner of typos, others in the company weren'y so dilligent and they very often go out unnoticed. What then happens is if someone spots it, the product company's PR Agency take advantage of the gaff. It's generally the staff in the products company's fault but they then blame the advertising agency. At no point does anyone claim the win apart from higher up the food chain in the client company, much later when it's all forgotten.
Not saying that is the case with yours but an awful lot of the time, they are just a product of high pressure, low skilled staff and multiple outside agencies working on campaigns.