Just switch from Time Warner and had Time Warner for almost 20 years and I can't remember when I seen an Emercency Broadcast System on there. They never went off.
Post 9/11 they got serious about Emergency Broadcast test. They are there now for all the OTA/cable/satellite companies. I think last year was the first test of a National test.
If you literally just changed and didn't see them on Time Warner then their was something seriously wrong with Time Warner service.
On brighthouse they are a small scroll text bar across the botton of the screen. Hence why I am canceling Fios and going back. Fed the hell up with required weekly tests happening every night.