You're right in that they only cover our SA neighbors, and Moz is certainly one of the countries.
In terms of not covering hazardous sports, and by extension, spearfishing: some time back I approached Discovery with this question. They said that spearfishing and freediving are fully covered. I then went one step further and asked by broker to send me a letter (on an official Discovery letterhead) confirming this. Which they did. So I made sure I covered my bases.
For others who are with Discovery and have similar concerns, I highly recommend doing the same