Even then, it didn't actually drop on them. They found it in the undergrowth and tried to pull it out. In total, about 9,000 balloons were released over a period of several months, and about 1,000 actually reached the US/Canadian mainland.
The United States government went to extraordinary lengths to keep information on the Japanese balloon bombs out of the media. The United States knew that Japan could only measure its success based on media reports. And giving them that type of intelligence information could cause them to refine the balloons to be more accurate and deadly. Even today, few Americans know much about the 'Fu-Go' bombs.