Lab leaks are extremely common, but usually benign.
Last month, I went to a conference in the UK. I was talking to some plant biologists who work with Arabidopsis thaliana, a weed in the mustard family. Arabidopsis seeds are tiny, like grains of pollen, and they stick to clothing. These seeds are often engineered with GFP, for example, such that they fluoresce green. And, being so small, they inevitably get carried (accidentally) outside the lab.
One plant biologist told me that that their lab group goes outside and picks all the Arabidopsis plants they can find in the areas around campus each year. They then bring these plants back into the laboratory and sequence them.
Last year, half of these "wild" plants had GFP.