That does actually make sense. A 200 amp receptacle protected by 90 amp fusing will be safe. The reverse would not be--a 90 amp receptacle protected by 200 amp fusing is in danger of being overloaded.
I think that the confusion that arises comes from the concept that a 200 amp load is going to be plugged into a 200 amp receptacle. When you're dealing with plugs and receptacles in excess of 20 amps, that doesn't necessarily follow. The cord, plug and receptacle are normally often selected at the time of installation; they need to be sufficient for the load, but there is no danger in having them too big.
The fusing is normally selected specifically for the load, so there's not really an issue with the receptacle and fusing having different values.
At 20 amps and below, the situation tends to be different. Specifically, if a load is supplied with a cord with a 20 amp plug, it almost certainly draws more current than can legally be supplied by a 15 amp circuit. And 15 and 20 amp circuits are pretty much generic--you find an existing receptacle in the wall, and plug into it. So, if one were to put a 20 amp receptacle on a 15 amp circuit, there is more of a danger that someone will plug in a load that needs a 20 amp circuit.
[This message has been edited by SolarPowered (edited 12-21-2004).]