Fairy Tail Ep. 097

[Kraco]

If it's an S-rank mission without much fighting, she might be able to. For example some region pestered by a magical plague that kills everybody, including any mages carelessly approaching. In such a case it would be extremely dangerous and deadly, yet no matter how tough a fighter the mage was, it wouldn't matter. Only brains and certain kind of skills would. I suppose such missions could be rare, and most extremely difficult missions not requiring fighting wouldn't be S-rank at all because trying and failing wouldn't be fatal.

[DarthEnderX]

I suppose such missions could be rare, and most extremely difficult missions not requiring fighting wouldn't be S-rank at all because trying and failing wouldn't be fatal.

That's what I assume. That S-Rank missions are S-Rank because they're the most dangerous. And most of the time, the danger is going to come from something that needs to be battled.