I do not have the 2005 Handbook.
However first and foremost whatever the handbook says is not code and can not be enforced or used as a reason to ignore the 2005 NEC.
In the 2005 NEC you will find 406.8(B)(1) you will find 'bubble covers' are required on every 15 or 20 amp 125 and 250 volt receptacle installed in a wet location.
Now look at the wording in 406.8(B)(2) it talks about about attended or not attended.
But that section 408.(B)(2) is about 'other receptacles' other being other than 15 or 20 amp 125 and 250 volt receptacles.
So if your installing a 30 amp receptacle in a wet location that will not be used while unattended than you can forget the bubble cover.
15 and 20 amp receptacles still get the bubble.
Construction & Maintenance Electrician