Lots of people are building their own and never have to deal with built in restrictions.
Here is the control software I use for the actual drone.
http://ardupilot.org/copter/
http://www.arducopter.co.uk/
https://en.wikipedia.org/wiki/ArduCopter
I use a program on android called Android GCS for onboard instrumentation.
https://play.google.com/store/apps/details?id=org.taulabs.androidgcs&hl=en
http://ardupilot.org/copter/docs/common-choosing-a-ground-station.html
Then I use Mission Planner for my ground control station.
http://ardupilot.org/planner/docs/mission-planner-overview.html
Everything you see here is open source and freely downloadable from the Internet. SInce its open source the code is readily available for modification. But why modify? There are no built in restrictions on what you can and can't do with it.
Next I source my parts from Hobby King.
https://hobbyking.com/en_us/multi-rotors-drones.html
For about $250 you can get a surprisingly capable quad rotor kit that comes with everything you need to start flying. Find someone like me who has the technical background to mod that $250 quad rotor and go all "tim the tool man taylor" on it. Beef up the motors and rotors to support a larger payload and presto chango you've got a poor mans cruise missile. Here are the instructions to include a 4G wireless communication system on board to really reach out and touch someone.
https://wiredcraft.com/blog/drone-copter-uav-4g-network/
Go with the same software and internals on a fixed wing and you can have a larger payload that can fly for 1000s of miles using the cell phone signal while you sit in a cave somewhere and bomb your friends and neighbors for fun and profit. Or just harass the police, fire rescue, or random women sunbathing topless.
So the technology is there to do just about anything you want. However most commercial off the shelf dones are not really capable of doing a ton of damage. The largest ones out there for sale are less than 10 pounds. Most are under 5. While a direct hit to a engine intake could be an issue I think in most cases the drone is going to deflect off the aircraft or just disintegrate on impact. Most of my stuff is light weight carbon fiber. I've had a couple of spectacular crashes that ended with just pieces everywhere.
Someone determined to do damage is going to do it right and will do a lot of damage but the idiots we deal with on a daily basis just looking to see something cool holding at 1500 on the approach to JFK isn't going to be a huge threat. I've see high speed impacts from drones and it wasn't that big a deal
Here is video of (I think) a pitts hitting a large fixed wing remote controlled airplane. The pits had very minor damage. Pitts do not have the structural capacity of a 737. So the boeing will suffer even less from a small quad rotor looking to get a cool shot of airplanes on approach.
Having said all that (as a helicopter pilot) I agree that unregulated drones are a threat to commercial aviation. A determined individual attempting to bring down a large passenger jet has all the tools they need to be successful free or inexpensively over the internet. However the hobby crowd does not present the threat that we pilots claim they create, unless you fly helicopters. Then you are just F'en stupid and are going to die anyway (do I really need to put a sarcasm tag here?).
I've had a couple of close calls in my helicopter and I will tell you I was glad to be wearing my brown pants that day.