You would have to call Comcast to get a ruling. I suspect that you're violating your TOS, but I'm not a lawyer. My reasoning is the HSI service is provided to a particular residence, not as a mobile service to YOU as an individual. This section of the Comcast Subscriber Agreement would seem to confirm my opinion, but I don't know if Comcast would have the same understanding:
6. Maintenance And Ownership Of Equipment
You agree that except for the wiring installed inside the Premises
("Inside Wiring"), all Comcast equipment belongs to us or other third
parties and will not be deemed fixtures or in any way part of the
Premises. Comcast Equipment includes all new or reconditioned equipment
installed, provided or leased to you by us or our agents, including but
not limited to, cabling or wiring and related electronic devices, cable
modems, multimedia terminal adapters ("MTA"), wireless gateway/routers,
any other hardware and all software or "downloads" to Comcast
Equipment. You agree to use Comcast Equipment only for the Services
pursuant to this Agreement. We may remove or change the Comcast
Equipment at our discretion at any time the Services are active or
following the termination of your Service(s). You agree to allow us
access to the Premises for these purposes. You may not sell, lease,
abandon or give away the Comcast Equipment, or permit any other
provider of video, high speed data or telephone services to use the
Comcast Equipment. The Comcast Equipment may only be used in the
Premises. At your request, we may relocate the Comcast Equipment in the
Premises for an additional charge, at a time agreeable to you and us.
YOU UNDERSTAND AND ACKNOWLEDGE THAT IF YOU ATTEMPT TO INSTALL OR USE
THE COMCAST EQUIPMENT OR SERVICES AT A LOCATION OTHER THAN THE
PREMISES, THE SERVICES MAY FAIL TO FUNCTION OR MAY FUNCTION IMPROPERLY.
You agree that you will not allow anyone other than Comcast employees
or agents to service the Comcast Equipment. We suggest that the Comcast
Equipment in your possession be covered by your homeowners, renters, or
other insurance. You will be directly responsible for loss, repair,
replacement and other costs, damages, fees and charges if you do not
return the Comcast Equipment to us in an undamaged condition.
By "Premises" they mean the address for which your Comcast HSI account is billed, not your father's house. This is all muddied up by the fact that he also has Comcast service, just not HSI, correct?
Thank you Baric for your rapid response. I do appreciate your answer. I do see a loophole in the agreement however. It says Comcast equipment provided by Comcast. My cable modem was purchased by me at Best Buy. Comcast has NEVER set foot inside my house. Therefore, IMHO, I am allowed to relocate my purchased modem to where ever I deem fit. Hmmm... Makes one think.
"YOU UNDERSTAND AND ACKNOWLEDGE THAT IF YOU ATTEMPT TO INSTALL OR USE THE COMCAST EQUIPMENT OR SERVICES AT A LOCATION OTHER THAN THE PREMISES, THE SERVICES MAY FAIL TO FUNCTION OR MAY FUNCTION IMPROPERLY."
In your case the word "services" applies to you.
I don't see where it prohibits taking your cable modem to another location, they simply say it might not work there.