If you are far enough away, you may not get sparks, but should still get some heat. With a tarp set up-behind you, it would likely keep you warm.
Personally, I feel safer when there's no open fire near me while I'm hammocking. Gladly, almost all of my friends prefer coal pit to open fire, so we usually don't have any arguments when we're on track together. I believe that others shouldn't decide your gear's fate, even if they were lucky enough to not experience something like this in the past. You're not paranoid or weird and your concerns are understandable.
Also this^
Safety first!
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