[Maarten88]

> Does this rule exist in any other sports?

In sailing, boats are required to render help to a boat that is in problems, before continuing their race. Boats that render help are compensated for the loss in position/time in the race afterwards, by a jury.

[reaperman]

This is generally just a de jure rule, very very rarely put into practice. In the vast majority of races, there are enough motorized “race committee” boats which render aid where needed, so the other racing sailboats wouldn’t be much help and don’t need to stop.

Long-distance coastal or offshore races it would be somewhat more likely as race committee boats generally are only at the beginning and end of the race. But even then, after hailing mayday, a good samaritan motorboat is far more likely to reach you first than one of your sailing competitors.

[plopz]

It's not so uncommon, I was just reading about Kristen Neuschafer and Yannick Bestaven who both rescued fellow competitors in solo races. Both happened in the last couple years.