Please, please, please don't think that you have to fly at 1,000+ feet to cause some serious mayhem for aircraft. Helicopters fly low, for multiple reasons. The majority of my time piloting a helicopter I am below 1000 feet AGL (above ground level). Helicopters are made for the types of missions that require you to be close to the ground, no one wants to get an aerial tour at 2000+ feet, construction work, utility work, fires, police, EMS, news, all of these missions require flight close to the ground. The FAA doesn't have a hard bottom altitude restriction on helicopters for this very reason. Airplanes may fly at just 500 feet above the ground. You may come across a myriad of aircraft at low altitudes and wonder why. What you need to know is first off; they are telling other aircraft where they are and ensuring safety... are you? Secondly; they have lots of training and education and are actively betting their certificate and their life on their ability to operate in a manner which is legal and safe... are you?
This is where the regulations are coming from from the FAA. They honestly don't care about keeping your UAS safe. They don't want you to fly a UAS into an aircraft (I promise it will do damage, from breaking a windshield, to destroying an engine, to causing the pilot to lose control because holy crap something just flew right at his face out of no-where).
Yes I am ranting. Both worlds are incredible, and I have a passion for R/C aircraft, as well as a deep passion for flying helicopters IRL. The thing is, when you launch a multicopter you are risking your equipment (read money), but what you need to be aware of is that you are risking the lives of others. No altitude at which you are looking, head tilted back, into the sky at your UAS is "safe", are you likely to encounter a helicopter at 200 feet AGL? Probably not, but you could. So if you hear an aircraft, and you see an aircraft, and you can't talk to that aircraft, land. If you fly at a distance that would put your multirotor outside the reach of a well aimed stones throw... then put it in a box, and go play hungry hungry hippos.
Whomever said it above is right... the first one to cause real damage (read risk, or loss, of life) with a UAS is going to absolutely ruin it for everyone else. Stupidity could easily make for some ridiculously expensive paperweights.
Rant over. Fly safe.