I saw your question a few days ago and waited in case someone knew what you're talking about. I have no idea what it could be. All I know is that I wouldn't want it if it's anything as you describe. Why would you want a tiled floor with plastic between them? And, I'll presume the tiles are just sittin there. I'd rather have a permanent some what watertight floor instead.
The only thing with a grid system I'm familiar with are raised-floor systems used in special computer rooms so the tons of wiring can be run under the floor. The floor tiles kinda drop in similar to the way suspended ceiling work.
Jaz