The weekend of Aug 19-21, the Upac event and the CYKF airshow both take place, eleven miles from each other. The air boss of the airshow and he was completely unaware of the Upac event and the potential for danger to the UL pilots.
The CYKF airspace will be notam closed from ground to 15000 ft, and the radius will extend 7 nm instead of the usual 5 nm. This will be the case for much but not all of the weekend. I explained that not many UL pilots would be checking notams when they have no intention of flying into CYKF so all that this does is to cover the airshow's behind but does little to warn the UL pilots.
The snowbirds and other jets will not always be able to remain within the 7 nm radius so at times, especially when arriving and departing, they can be flying day VFR at low altitudes anywhere in the area. Also even on a normal day with a 5 nm zone the tower frequently sees UL targets inside, shortcutting across the edges. This is a recipe for a midair on that weekend.
Any intrusion by ultralight / aircraft will result in the airshow being stopped, and since TC will be present they will pursue enforcement against any pilot who breaks the notam airspace. Again, it is 7 nm, ground to 15000 ft. For reference, 7 nm gets right to Roseville.