Hey Kermit, what about something like this attached to two ropes that is taken up by a drone and put around the branch that the grass hopper is stuck on:
Working the ropes back and forth on the ground may eventually cut through the branch?
Permission could be sought from the owner but I don’t reckon he’d worry about one branch.
What do you think?
Rope saw’s are also available but they are a lot more expensive and I imagine they would be quite heavy.