All systems, as they take away the need for extra adhesive to be used in voids, and allow weaknesses to be created, thus increasing the chances of tile failure.
The old and safe method is to:
1) Make sure the surface to be tiled is sufficiently flat (+/- 4mm over 2 metres)
2) Make good the surface if out of these tolerances with levelling compound on a floor or plastering/re-boarding walls.
3) If bedding up with adhesive is necessary on a floor like yours, it is best to lay the tiles, and use extra adhesive to eliminate lips, up to the tile adhesive limits on depth.
Simply lifting a tile off the surface using these systems, does not apply extra adhesive underneath the tile, and will therefore create a void where the tile is not bonded to the surface. This will create a weak spot in the tile, which will be prone to damage.