By trade i am a designer, and we as a rule make the client sign off any artwork. It amazes me the speed of two things...

a) the speed in which they manage to proof read and sign off artwork - literally in seconds.

b) how quickly they will spot an error the moment they recieve the printed item.

What drives me crazy is text talk on forums, or on things like car adverts, as said above, if there are two cars both the same but one advert is written in the manner of a chimp with limited experience on a keyboard, I will look to the other.