In article , David
Johnson wrote:

I know that there are those hereabouts who will dispute this, but it is my
observation that airplanes with winglets produce more violent wingtip
vortices than those without.

B757's and B767's are known for their violent votices; even the 10 mile
spacing mandated by the FAA is not always sufficient to keep trailing
aircraft from being bounced (especially light, GA aircraft).