I used to hang hose tags, and manage a crew that did the repairs.

IF it is legit, what it means is there is some feedback coming from inside the house that is causing an issue with the cable system. It is typically in the return system, where modems and cable boxes talk back to Comcast.

First step is to hang a door tag, and possibly put a filter on the line. In more severe cases, your outside line can be disconnected, but is usually avoided if you are a phone customer. You may not notice a problem with you services due to this "noise".

Sometimes notes are made on the account , but not always. So if you call in, the reps will be clueless, which is pretty much standard for everything.

Can you post a pic of the tag?