everyone on Alone has bear repellent. But that has to be used correctly and be timed correctly. If nothing else it will interrupt a maul if not completely stop it.
They are alone and who knows what will happen here. I don't think this is a series but more of a oner. It does seem like the guys were carefully selected to not make foolish decisions and I appreciate the lack of narration. The guys do their own videoing, no contact until they call to be retrieved. They probably have to check in with the crews x many times a day though, can't just let them disappear.
Now on Naked and afraid - there is a camera crew during the day, but they are alone at night videoing themselves and if they have a fire and are cautious, they can avoid an attack. They have not gone back to the Serengeti since the first year when the animals got very interested in the people. Some people have drunk unclean water and became ill for months on this show with some pretty scary diseases. I hard that one cameraman on N&A was bitten by a poisonous snake and they were scared they would not get him help on time, but he did survive. I think being naked and without shoes makes you way more cautious. A lot of the shows are pretty boring with them just waiting their days out while starving.