First... the original post said the field had a legitimate fire hazard problem with jets. Right there is sufficient reason for the website to state that Jets were not accomodated.

Maybe just the wording of the jet limitations on the website needs to be altered to reflect that its a seasonal fire hazard, and thus state that durring June to Sept (or whenever the hazard is normally excessive) that turbines are not allowed. (should it also apply to Gasoline powered prop driven planes as they can be a fire hazard in a crash too?)

Look for the easiest solution first.