Hi @Erica1225, your bed does need reinforcing to be suitable for a variety of body weights.
As mentioned by @Anonymous, improve your house rules for checkout requirements. Make sure they are in the listing details and in your welcome folder. Can also be sent with a reminder before checkout. ( less practical when only an overnight stay)
But to be honest, the negligence of leaving candles alight is paramount.
A kitchen can be cleaned, a bed can be repaired, BUT a place burning down is more the concern from this negligent action. I would NOT be recommending anyone who was that clueless or disrespectful about someone’s property or its safety.
For my insurance a few years ago, I changed out all nice smelling real candles for battery (NEVER button sized) operated candles. I also add some LED warm white little fairy lights in the space for extra ambiance, if they are wanted. These can also be used as night lights for kids. I also placed the matches for the barbecue in a container not so easy for kids to open, in a cupboard that’s up high.