The iPad is not carrier subsidized hence it cannot be locked. There is no mandatory provision by law in the US for iPad's class of device to be locked to any carrier, neither is it locked in any countries beside Japan currently, which is locked only because of governmental mandate.
The wording in the Appls US Online is a comparison between ATT and Verizon models which shouldn't be taken out of context, since both utilizes different cellular technology. It is a precautionary measure to ensure consumers do not mistaken the either model will work on the other.
If you read the paragraph properly, it says "specially configured to ATT or Verizon". We know the iPad 3G models that was sold last year came with an ATT sim card, which was specially configured for immediate 3G subscription from the iPad. This is what it means by "specially configured". I don't get a sim card when i bought mine, and I had to subscribe to a data plan before I can get a sim card from my carrier. An iPad specially configured to ATT will not work for Verizon and vise versa. Read the paragraph within the contextual boundary of ATT and Verizon.
Like I said, classic Macrumorian paranoia.
Agreed