Thats right Dave...

the metal box for charging is redundant, those rules were drafted up before lipo sacks were easy to get hold of... get a lipo sack. There cheap enough on Ebay these days.

At tech check for people using lipos i check for the following;

2mm+ METAL base plate under the lipo + security of the lipo (I.E. It isnt cable tied to the pneumatic cylinder *cough* Mr Lear *cough*)
Secure well insulated connections within the robot + the connectors being used are sufficient to cope with the maximum current draw.
Sufficiently rated fuse on the positive side of the lipo, thats rated below the maximum discharge of the lipo.
The visual state of there lipo
The charger + balancer combo the competitor is using is suitable
The competence of the person using the equipment.

Im a bit more strict then some tech checkers when it comes to lipo's, but most of the people using them so far have enough common sense to think of all that them self.