Since we design websites and print marketing materials, I always have the terms about 3 lines in my email signature, regarding to what we are not responsible. Like checking spellings, etc.. So, they know they will be responsible, therefore they pay attention. But if they need something to get fixed in their website or for example the print has problem, of course we take care of it. The best way is to be grateful in our services and be clear about all necessary details from the beginning to avoid these confusions later.