Too romantic and too complicated. Just send a signal to detonate the sob when required intelligence has been received. Why wait till the sob descends? Just do it and raise the middle finger to America.
The reason I suggested what I did was to ensure destruction of the critical components in case the balloon is shot down. In that case the package starts to fall quickly and may fall into hostile hands, broken, soaked or otherwise. If the equipment self destructs on the way down, then the hostile power gets very limited information from the wreckage and the wreckage is spread over a larger region.