Probligo is right to some extent. The aerofoil does "create" some of the vorticies itself, but only by design. A thicker aerofoil generally will creat greater vorticies due to the fact that the upper air has to travel that much of a longer distance in a given time fram making it travel faster with even lower pressure. The lower pressure, as compared to a wing 1/2 as thick, will make a greater vorticies potential.
The fact of the matter is that the vorticies actually do NOT form on the wing. The vorticies starts at a small distance off to the side of the wing depending on aerofoil design. A longer thinner wing as used in Probs example will create the same amount of vorticies, but at a reduced rate of swirling effect at the tip.

ANYTIME a wing is creating lift, it IS creating Vorticies.

Now as to why airliners are using raised wing tips is simple. Remember that Wingtip Vorticies swirl and that motion has a speed. So what they are doing is diverting the vorticies from coming off to the immediate side and put this air motion OVER the wing! This gives the wing anywhere from 2 - 5 % more lift!!! The greater the lift adds the benefit of letting the aircraft fly with less energy imparted to the aircraft by the engines. What this means is that the engines don't have to work as hard to make the same amount of lift. In a sense, they are doing to the wing what modelers have been tring to do with weight on airplanes! If you have to have the weight, you might as well make it USEFUL weight!! That's the only reason that they are going to the raised winglets! it allows the airplane to operate the same, but with slightly less cost (gas / trip.)

Just my 2 cents worth.

Thanks,

Reg