I actually think the rifle form factor is a horrible idea in use, due to people flipping out when a rifle is pointed at their building. But for shock value, it wins.
The ideal is probably to use a panel antenna on the back of a laptop, or some non threatening way to conceal a higher gain antenna. It would be cute if someone put all this in an SLR camera form factor, I think...a 70-200 f2.8 is big enough for a high gain yagi.
This is a beyond horrible idea, it could easily get you killed. Use it in an apparently offensive manner, i.e. point it at someone, and the shooting would even be justified, unlike at least one of the two above incidents.
+1, it's not a good idea to use a rifle form factor. A good hack, but a bad idea considering others' reactions. I'm pretty comfortable with guns (raised in more rural Idaho), and I'm not particularly keen on the idea of seeing someone point a "rifle" out their window.
Sadly photographers often get hassled if they take photographs in public. At least, the do in the UK. It got so bad the Met police had tonissue guidelines to their officers about why it's okay for people to take photographs in public. http://content.met.police.uk/Site/photographyadvice that advice is written from the lerspective of the Police. It doesn't mention the extra protection given to journalistic material for example.
So, while it's not going to get you shot using a Hack-DSLR might get you arrested.
I've been "harassed" a few times over seas. Usually it involves accidently photographing near police stations or military installations, which is a pretty obvious no-no, except that the buildings were pretty non-descript and I had no idea what they were at the time.
It's only happened a few times: someone comes out and either tells me to stop, or yells at me in a language I don't speak very well, and I say "sorry" in whatever language and continue walking around.
I find that the trouble happens when photographers/travelers try to argue with the people harassing them.
Usually most the people I encounter just make a joke, smile, and encourage me to take photos.
Funny how far a smile gets you when you're traveling.
In the US, you can modify a gun pretty much however you want (short of making it fully automatic, having a barrel that's "too short" per regulation, or building any form of suppressor).
But of course this is an airsoft gun, which you can modify to your heart's content.
As long as you are not using a lower receiver [1], it's not actually a rifle, just pieces of metal and plastic. The lower receiver is the actual firearm according to U.S. law. For example, these [2] are the non-rifle parts of an AR-15.
ITAR applies to certain accessories as well (optics, some suppressors, and I believe certain muzzle brakes). That's only an issue for export, though.
(and the "lower receiver" vs. "receiver" part is only for the AR-15 or rifles of similar design; lots of rifles have a single receiver, and for handguns it generally means the frame -- it's in reality a circular definition, with the receiver being the serialized part which is serialized because it's the receiver...)
It's really interesting with firearms like the Sig P250, where the interchangeable piece is on the "fire control group" and the rest of the firearm is totally interchangeable -- this is specifically because German regulations restrict people to owning two handguns, and this lets you have one firearm in multiple calibers, sizes, etc.
(Amazon's policy is even weirder..."anything in the firing path" is prohibited, but a lot of other accessories are commonly sold, and the policy isn't really uniformly enforced at that.)
Plus, in some countries they restrict airsoft and pellet guns (like this one) based on muzzle energy (or sometimes velocity). 3-6 J is a common limit.
Not in the US, up to a certain point. Certain kinds of weapons and weapon shapes are regulated.
As a rule of thumb, historically US law has reflected the following, "If it's not explicitly banned, it's OK. And if you do it while banned and it is kind of awesome, the law will change". This has changed considerably in many areas, but still generally holds true as an ideal.
edit: let's not downvote someone for asking a reasonable question. lots of places exist with lots of regulations.
