1) Unless you're really trying, it's pretty difficult to burn down the neighborhood with a science kit. When using a cell phone jammer it's pretty hard not to affect all the people around you. That's kinda the point. Now, if you don't want cell phones used in some place that you own, then paint the walls with signal-blocking paint.
2) Have you tried to buy a chemical kit lately? They took out all the fun stuff years ago.
Unfortunately, declaring "EM freedom" is pretty much incompatible with the idea of using the EM spectrum for anything useful. If my freedom to actually use a cellphone or a wifi network conflicts with your freedom to make a 10 kW roving-frequency 24-hour bagpipe music transmission, how do we resolve that one?
This isn't really a hypothetical problem either -- if anyone could broadcast anything at any frequency at any time I'm pretty sure everything would fill up with ads of some kind.
Your rights end where mine begin. As a libertarian I believe that you should be able to do almost anything to yourself. Start monkeying other people's property/body/space and I'm against it.
update: Hey, why am I being voted down? Not trying to be a douchebag here. I really do view EM freedom as strongly correlated with normal-speech freedom. "Pirate" radio stations anyone?
Clamping down on "rogue" EM radiators is like clamping down on "rogue" anything else. We need a broader definition for "freedom of speech". EM is speech, too.