They might burn candles all over and ruin the carpets and burn countertops.

I've been in NuSkin, and exposed to Amway, Herbalife, and any number of candle and nutritional MLM's.  

In our case it was carpeting in the master bedroom that the tenant ruined with candles that we replaced with laminate.

And in the real estate case I would struggle to assemble the evidence needed in an audit defense, especially as I live in Asia.I need to consider whether the game is worth the candle, so to say.

I would also recommend citronella candles in the summer.That's what I would do.

For the record I am not a hippy at all, just an architect landlord.

The image that you have of some hippie bum with no job simply doesn't match the pot-smoking population at large - responsible adults don't let you know that they smoke weed if they don't want you to know.

The house was spotless and I had autumn scented candles burning when I showed it, a few fake plants in the kitchen.

However, if they are complaining a couple of months into the lease and they knew about the smell before the decided to move in and you didn't mention anything about removing the smell prior to the move in date, I would tell them to light a candle.  

However, in those instances we do inspect and keep a watch to make sure food is not rotting in a fridge, pipes are not freezing, candles are not being used as a light source, etc.