John,
I think they were just trying a lead in to the correct verses incorrect examples later on in the article. Like Fig 2 compared to Fig 3 & 4. That said, showing the number of incorrect examples in this particular format was not the best choice. It's actually kind of confusing. There is after all, one correct way to draw a symbol, and there could be a great number of incorrect ways. It might have been better to have more examples like Fig 5 & Fig 6
Bouncing from customer to customer, I see a lot of errors on shop drawings and on the transferred information marked by the layout guys. Backwards fillet symbols like the one in Fig 3 are common. Some shops keep their drawings very simple, with respect to views and symbols. I even have one customer that rarely uses the other side of the reference line. The arrow always points to the location of the weld.
I've seen the photocopy funnies of welding symbols for 30 years and they still crack me up, you know the ones I'm talking about.... the fish on the reference line that is titled "fillet weld", or the one with the boat titled "ark weld", or the one with the $ in the tail tiled "field weld".
~thirdeye~