I analyzed the still photos and looked at the definition of assault.
http://www.greengonzo.com/dictionary/Asault.html
"A violent onset or attack with physical means, as blows, weapons, etc.; an onslaught; the rush or charge of an attacking force; onset; as, to make assault upon a man, a house, or a town.
A violent onset or attack with moral weapons, as words, arguments, appeals, and the like; as, to make an assault on the prerogatives of a prince, or on the constitution of a government.
An apparently violent attempt, or willful offer with force or violence, to do hurt to another; an attempt or offer to beat another, accompanied by a degree of violence, but without touching his person, as by lifting the fist, or a cane, in a threatening manner, or by striking at him, and missing him. If the blow aimed takes effect, it is a battery.
An intentional threat, show of force or movement that causes a reasonable fear, or an actual physical contact.
(fencing) A non-competitive combat between two fencers"
I further analyzed the photos and can clearly see a reflection of BobK standing motionless with both hands on the camera in a non threatening way.
The paraglider instructor was kiting without a helmet. This is fine when there is no chance of launching and no solid aircraft in the air.
The paraglider instructor turned towards BobK and ran at him as if he(instructor) was possessed by Quetzalcoatl (an Aztec God that feeds on human sacrifice).