Its a bad idea to run a server off of cable anyway. The good pings are misleading. Cable modems have great download, but terrible upload. You need good upload for a good server. Maybe a cable server can handle a 1on1, but thats about it. With 10 people on the server, I bet the players are experiencing weird problems, despite having good pings. When I am on a cable server, everthing will seem fine, but whenever something happens, (like someone grabs my flag, or a bunch of rockets explode, or a bunch of people enter my field of view) I get weird lag. Anything that would require the server to upload a bunch of stuff to me (and to 9 other people) is gonna cause lag. If you are running this as a pub, please identify it as a cable server in its name on the server browser, so I can avoid it.
In answer to your question, I am on Cable, and my pings have been terrible everywhere since the Napster deal. It could be a coincidence, but my pings have gone from an average of 100-140 to an average of 250-350 on all my favorite servers.