Wormy Notes:
At Rotation.org, we typically ALTER LESSONS that suggest the use of a candle or open flame, or the creation of something like a candle project that kids might be tempted to go home and light.
We've even nuked lessons that suggest setting a gas on fire as part of a "science" demonstration!
Every Sunday School teacher needs to know where the fire extinguishers are.
If you are creating a tent out of non-flame-retardant cloth, then you might consider locating a fire extinguisher IN that room. The odds of having a fire inside a creatively decorated room are extremely extremely low, if common sense is used.