bildan wrote:

Lets say, just for argument, that a rope below 1500' AGL would not
deserve a NOTAM but that over 1500' it would. So how long would the
rope be above 1500' on a 3000' launch? My educated guess is that
would be 15 - 20 seconds.

15 to 20 seconds are plenty enough for disaster. But I didn't mean it
literally. (Albeit, the 5000 feet launch in the linked YouTube clip did
require a NOTAM.) Anyway, I didn't mean it literally, but just wanted to
point out that a long rope will interfere with power traffic. This is
solvable, of course, if you have a plan and everybody cooperates. But
you definitely do need a plan.