I would (and have in the past) go outside with a torch, shine it onto them and politely ask ‘Hi there, is everything OK?’ When they reply that they are, say (sweetly) ‘ah, that’s good to know. It would be wonderful if you could keep the noise down for the sake on the neighbours. Thank you SO much. Have a great night’.
Job done 
I agree that it’s good to have issues documented on the Airbnb platform though.