The NOTAM system doesn't always make it easy.
I posted the NOTAM here about the mass microlight Channel crossing on Saturday, but, as far as I can see, you'd only have been aware of it normally if you'd happened to specify Lashenden/Headcorn in your route briefing, in spite of the fact that the event affected a corridor form there to Abbeville via Ashford, Cap Gris Nez and L2K.