Maris coughed up some electrons that declared:
Forgiven :)
Yes, it might do. The mesh will definitely give a bit of reinforcement once buried in the flexible grout - incidentally, I would try to get the most metally flexible grout and tile adhesive you can find for this application. Mapei do loads of specialist products and their technical line can advice what you need.
If I were doing this, I would do a trail run of one tile on a small offcut of marmox on a paving slab. Then see if you can break it - bit of tap dancing, phone a (fat) friend, that sort of thing.
Assuming the bathroom has a bath, I would most definitely put the bath on 8" wide, thickish[1] bearer planks. The bath will go up an inch or so, but you'll have peace of mind.
[1] Thickness depending on wood type.Cheers
Tim