Why are we assuming that this was the (only) lesson Chazal learned from this story ? They were demonstrating how something considered minor could have drastic consequences, and simply used this story as illustration.
It does seem to be very unlikely and random outcome, and so am not sure how it really serves as a motivation to keep the halachah.
its not really normal to treat everything in the world as a matter of life or death, just because it could theoretically serve a s a catalyst for such.