Actually, there's some truth here.
On March 11, 2005, the FCC released a set of rules outlining an alternative method for certification of devices whose radio frequency and power characteristics can be modified by software (such devices are designated Software Defined Radio devices). The rules allow manufacturers who have certified under the new process to update the software on the devices without re-certifying the devices with the FCC.
The rules require any manufacturer certifying a device under the new process to take steps to prevent “unauthorized” changes to the software on the device that might alter its radio frequency and power parameters in a way that takes it out of compliance with the regulations known as FCC Part 15 regulations. The specific technology implemented to accomplish this task is left to the manufacturers seeking certification, although the FCC suggests several possible mechanisms that can serve as such “security measures.”
The implication is this: If the FCC thinks that a device does not (no longer) preven unauthorized" changes to the it can obviously revoke its certification and followed by other consequences.
Failure to Comply with FCC's Regulations
... The FCC has authority to assess a maximum forfeiture of $11,000 for each violation, or each day of continung violation of its rules, up to a statutory maximum forfeiture of $97,500 for any single continuing violation."
[NOTE: The text goes on and list an example of a $1,000,000 fine. So you might want to read the whole text]
This "fact" is scaring every vendor, because they will have to pay the fine if the device does not prevent such unauthorized changes for each unit they've sold there. Therefore they want to limit the damage that an "unaware" user might be capable of doing.
However, back to the HP talk. While there's some truth in the FCC ruling, it should only affect wifi card vendors like Atheros, Broadcom, etc. and not HP [Of course, you could argue that HP is responsible for the Antenna design and layout, but that's just a tiny, tiny piece]
Note: This whole "regulatory hell" is also the reason why wireless is such a problem for open-source operating systems. It's because some hw vendors decided to implement the restriction in the drivers, as it saves them
a lot of money since firmware code or hardware is much more expensive. So they can't really release an open-source driver without fear.