Well, a few things about wireless transmissions...
My normal job has me knee deep in wireless units, Radio mics to be exact.... The highest end units available... (some would argue) with the best antennas and computer assisted frequency finding programs with serious filtering to help keep other transmissions from getting to the frequency were using.
It always boils down to a few key situations... actually a lot of them, but a few are really important...
Surroundings... buildings, metal, fencing, competing transmissions and transmitting power.
Line of sight is always best... we avoid putting anything between our transmitters and the receiver antennas... being buried in a neighborhood between two story homes is a poor place to be in general terms... open fields, or any open areas are much preferred. Frequencies move much better through trees than through structures. Organic things don't affect us too much.. People though actually do... lol.. If someone stood in front of your controller, you would suffer range issues I am pretty sure.. it definitely affects us... I am always clearing people from in front of our cart.
Also, the interference caused by any number of things on the same or really close frequencies can wreak havoc. The expenditure on the wireless gear in this drone and controller are in the low hundreds of dollars, OK, and totally functional, but not great in any way.. In comparison, the gear we use is thousands of dollars and has all kinds of serious technology... it still has issues we often need to work around.
I would only say that knowing what I know, I probably will be really careful not to place myself with that controller in any situation I would not place myself in at work. Mainly buried somewhere in homes, neighborhoods and at the bottom of downtown buildings with both obstructions and elevated amounts of other radio activity. Problem is, at work we don't get to choose.
Key is... line of sight in these situations as best you can, always..