I flew with them last month and what a breath of fresh air it was to be able to arrive at the terminal (the site of a PPRuNe Bash about 4 years ago in the Flying Beaver Bar), check our bags in and board the aircraft with none of the hassle or BS that goes with air travel these days.
Of course, it is only a small single engined turbo Beaver, about 16 seats and single pilot ops. Even if someone was stupid enough to try and hijack one of these they aren't going to go very far or do tremendous amounts of damage in a suicide mission.
The expense and hassle factor alone outweigh the risks. Leave them alone I say. One of the last bastions of enjoyable air travel. Let the Senator have his grandstanding and soundbites. I wouldn't trust any politician as far as I could throw them, especially when it comes to aviation security. As pointed out above, the ferries are a much bigger target and there's no security checks there.