Jack, I had some 20d nails that I used that I drove into the 2 x 12 gable fascia. The tie off ropes at the top of the ladder are to keep the ladders from shifting right or left, NOT to prevent them from falling completely from kicking kicking out at the bottom. Stakes or heavy ground materials securing the feet (when on dirt or grass) are used to keep the bottoms of the ladders secure.
Appreciate you noticing the safety measures. I'm a commercial roofing contractor, so I set up every job where I'm off the ground so it would pass OSHA standards. All ladders are tied off at the top, stakes are driven into the ground when they are on dirt or grass. Walkboards are level and tied off to the ladders, so they can't slide around or shift. If the walk board is positioned out side the supporting ladders, I use a third ladder for going up and down (which is also tied off & staked), to make it easy to access the walkboard. Bee boxes are straped down to the walkboard. Also have a fire extinguisher present. Last, but not least I have a safety line and wear fall protection while working.
I'm to old, not to be careful.
Sorry to be so wordy and preaching, I don't know anything hardly about bees yet, but I do know construction and roofing.