Ooh! That is interesting.
How did you spool the tape measure up on the robot end? How was it attached to the drum? I'm sure the solid tape was in no danger of failing, but I'd be worried about pulling out at the holes if it were riveted to the drum. Then again, I've never done load testing on a tape measure, and really don't have a clue how strong the stuff is...
Were you worried at all about a failure from being hit while you were in the process of hanging?