I took a group of Sims camping a few days ago. I was play testing to see if or when a Sim's ability to sing campfire songs was present. Those Sims had some issues with the campfire. They weren't fireproof, but 4 Sims put the fire out. However, one guitar and one stone chair got charred.
Then, my main Sims went camping, and they've all completed the Freelance Botanist aspiration. However, one of them was briefly on fire, but it went out. I had her husband extinguish the fire on her and the campfire. She didn't get the experienced a fire moodlet.
That lot only has the good acoustics trait.
However, my main Sims guitar and stone chair got charred, as well --- even though my main Sims are fireproof.
I'm not sure if this is another issue, but I can't place my Sims' guitars back into their inventories, and they don't seem to do it.