OK - I know that using a steam mop on any type of wood flooring is generally not advised by manufacturers or installers, and for good reason. I clean houses for a living and I have seen where customers have stripped the finish from wood floors with over zealous use of the steam mop.
BUT - What about using a commercial dry steam vapor system? What I am talking about here is the type of machine that has an adjustable pressure output and emits no more than 5% moisture in the vapor produced. These machines are made by companies like Daimer and Dupray.
I have been using one on engineered floors and solid for about two years with no adverse effects, but I want to get the experts opinion on this because I have been moving up to doing larger, high end homes with LOTS of wood, particularly bamboo. (I know I really should have posed this question to some experts sooner, please don't berate me.) My method is to use the lowest pressure setting and to use bursts instead of continuous vapor output so that the mop cloth is only slightly moistened periodically. On laminates, I lift the mop head from the floor before releasing steam into the cloth, because I am afraid that if even a very small amount of steam were released over an area where the planks meet, the moisture might get in between them and cause damage.
I've seen a lot of info online about steam mops and wood flooring, but not on vapor cleaning and wood flooring. Seems that the flooring industry hasn't tested out this technology yet.
Of course it is something that is currently not recommended by any manufacture, that I know of. However, steam mops and vapor cleaners can be used safely at commercial locations.
Funny as it may seem the laminate floors seem to hold up well to the harsh heat, better than the woods.
The wood floors, I would not use them on a regular basis, unless you have extreme grease that you need to cut, and then keep in mind that he flor wold have to be replaced sooner. In moderation (monthly), It would most not effect the life of your customer's floor, especally beingthat you are being careful.