I enjoyed the article-I could certainly come under his 'shark' heading-an older autograph hunter,possibly getting a number of cards signed,sometimes in pristine condition,but I am a collector not a dealer,so you can't make assumptions on everyone.
I have often been asked if I am selling them which I always answer it is for my collection,and as I normally have other items on me which are multi-signed,they usually realise I am telling the truth.
I actually agree with one of the replies to his statement,that unsigned cards (especially the older ones) sell for more than the signed cards,so in some cases,signing the card may actually devalue it!