I don't know how anyone in their right mind can let someone else fill out their application forms and then sign at the bottom without examining the contents of the filled forms. Are they aware that by signing they're acknowledging that all the filled out information is correct? The government doesn't care who fills out the forms. The person signing them is responsible for their content.
It reminds me of the Border Security episodes I watch (there are many versions of them, the Australian and the Canadian ones being the most popular). The customs agent examines the contents of the traveler's suitcase and finds what looks like drugs. He then asks the traveller "What's this?" and the traveler says "I don't know. My friend packed the suitcases for me." To which the customs agent responds "So you don't know what's in your luggage?"
How can you not know what's in your own suitcases? More importantly, how can you not inspect your own suitcases if you let someone else pack them for you? How do you know they've not put drugs in there?
It's the same situation with lawyers and application forms. This is your application, not theirs, so if u don't examine what's filled in the forms, you're asking for trouble. The lawyers will make mistakes all the time, and you'll be the one responsible for them at the end.