This supports my belief that the FAA needs a better obstacle flagging system, something like ADS-B, which can transmit for all obstacles, including temporary ones, and mandatory ADS-B In or matching receivers with warnings set on proximity the way the FAA depicts in their videos on the subject. Keep in mind they don't need to be located on the obstacle, they simply need to be in sufficient proximity to provide sufficient range, like at the base of a broadcast tower where power is readily available and the unit is accessible for installation or repair. In this case, along with the NOTAM a rental/loaner ADS-B Out programmed with the details would be issued to the tight rope installers.