I think a lot of this chipboard question can you/ can't you
tile straight onto it needs to have a lot of variables taken into account. Such as 1. size of floor 2. movement in the floor prior to tiling, 5. what room the floor is in and 6 what is the usage of the room.
For instance, a small shower room of say 2m2 with a solid floor, used by two pensioners is much less likely (I feel) to have issues than a 10m2 family bathroom floor with 5 young kids splashing about and running around in it every day.
The first scenario I would more than likely
tile straight onto it, where as the second, I would really need to overboard it.
Modern adhesives are pretty good and if the manufacturer says they should be suitable, then maybe we should trust them, shouldn't we? I think common sense needs to prevail sometimes and a judgment call made based on the conditions and situation at the time.
Just to stimulate debate, what are everybody else's views on this?