I don't think that's the case, because I see movies with Arnold in them all the time on cable. I think it may only have to do with shows that are first run, or are re-runs on the same network on which they originally appeared. In that case, as soon as the new season of "Law and Order" begins, he'll be free to engage in a full campaign.
So if ABC was to show T3, they had to do something else for the affiliates in CA, but FX or AMC were ok.
Same with L&O as I understand it. On TNT it should be fine, but not on an NBC outlet. I think we are about to see that tested though. This happening at the national level is new ground. There maybe changes already, my buddy John has been out for a couple of years. As far as seeing Arnold now, the race is over. It will be interesting to see how that plays as the next election nears. I guess they will wait until someone cries foul...