Since the language only seems to preclude fostering “for other businesses or organisations”, a person who was fostering privately, not for a rescue or shelter, wouldn’t be prohibited.
I always try to find temporary fosters for my foster cats when I travel. However, there was one trip where I just couldn’t find another place and the sitter took care of the fosters, which were in my listing. The cats had lived in my home for a few months at that stage, so they were no longer adjusting or stressed.
Carla mentions that “. normally fosters are in the process of settling and decompressing, and they might find it too hard to adapt to someone new so soon…” The same concern could apply to any newly acquired animal, whether fostered or adopted.
Maybe I should start reporting posts that mention cats bringing dead mice or other prey into the house. They should be prohibited based on clause 5.2.4 - “ensure that…no pets… have ever caused a person or animal any physical harm (no matter how minor the injury).” 
The dead mouse’s injuries were definitely not “minor”!