whose idea was it to use metal detectors as gun detectors? Time & technology change... and detection methods must change with them.
If non-metallic guns were truly viable, they would have been used 20 years ago to sneak past metal detectors and kill judges and politicians and airplane pilots. Plastic manufacturing has been around for a long time, the only thing 3D printers do is reduce the cost. There are well-funded spy agencies and a few individuals who would have paid hundreds of thousands of dollars for a single gun. And yet none has materialized:   
I can only speak to how my local hackerspace handles it, I don't know how others do.
At this one, most power tools are owned by individual members. If someone gets hurt and wants to sue someone, the only person they can sue is the individual owner. On one hand, this sucks because it puts all the burden on individuals' shoulders. On the other hand, it decreases the chance that someone tries to pay legal fees from prospective damage awards, because damages are likely to be very small, so it reduces the chance someone will lawyer up.
Our hackerspace hasn't had any incidents yet, so I don't know how well this plays out in practice.
The goal isn't to develop fancy new hardware, or to use an overwhelming amount of power. The goal is to develop fancy new software.
With frequency-hopping and time-hopping techniques, if you can intelligently adapt to the local interference, and transmit in the time and frequency gaps where the interference doesn't occur, then you can transmit more data for the same amount of power. That's the goal.
But isn't it difficult to get a RAM dump, you say? Not really:
- Hibernating a computer writes this data to disk. Starting in Windows 8, "shutdown" actually writes some hibernate data by default.
- VMs also have their own suspend functionality that does a RAM dump, as well as non-SAN VM migration.
- Firewire ports actually allow devices to scan RAM of the machine they're connected to.
- Obviously, if you have access to a live machine, you can get the keys directly from RAM.
Interesting fact — There's an 85% fatality rate for the speed record for any boat. This sport is extremely dangerous.
The sailing speed record is 80% slower than the overall boat record, so the sailing record is a little safer. Nonetheless, one of the SailRocket crashes led to the pilot having a broken helmet.
AVR-Stick, by Reusch Elektronik
The term "SCADA" is specifically used for industrial processes that have to be connected by long-distance networking.
(it's a slight variant of your #2, though "compromising" in this case doesn't mean a full compromise, it means mildly abusing the DNS spec to work around XSS restrictions)