Frequencies
I still feel that adding local NOTAM information onto the end of the ATIS would be a good method - receivable by any VHF radio or scanner, or by phoning Volmet from the ground, but let's say we're not allowed to do that.
The obvious other place to put it would be on VORs - you could manage pretty much nationwide coverage that way without a single new frequency, albeit that presumably some black boxes would need adding to the ground hardware.
Of course none of this will stop a complete idiot not bothering to check anything, but I prefer to believe that nobody actually wants to fly dangerously or illegally - but they do tend to if it becomes too much hard work to comply with the rules. I think that at the moment a lot of people simply find the current system too much hard work. I suspect that a broadcast system may well cause a lot of people to not read NOTAMs that aren't close to them, but for safety purposes that should be enough to ensure no repetition of the sort of thing that happened here.
Incidentally, a couple of years ago I went to the "International Rocket Weekend" in Largs. Rockets were being launched up to about FL50 - this was NOTAMED. I counted about half a dozen aircraft per day through our overhead below that height, at-least two of which were Islanders - presumably Logainair and certainly not PPLs.
G
N.B. Wasn't this all the sort of thing everybody worried about when NATS was being privatised?