You bring up some very good points that I can definitely vouch for from personal experience. My wife is a nurse in North County San Diego and a lot of her co-workers commute from Temecula, Murrieta and Menifee on a daily basis because of the cheaper and more affordable housing available up there. A lot of these people grew up in San Diego County and have most of their friends in SD / North County so they are definitely more interested in San Diego radio stations and news than that coming from LA. My brother-in-law does the opposite: he lives in Oceanside and works in Temecula, but listens to San Diego radio stations while at work in Temecula.
On the television side, I believe that KUSI, an independent television station in San Diego, has a translator up in Murrieta so that tells me that a lot of displaced San Diegoans live up there and prefer San Diego news on television and the radio since they do have a focus on Temecula news and traffic. KUSI has news stories about things going on in Temecula and KOGO AM 600 from San Diego gives traffic updates about the I-15 through Temecula and the I-15 / I-215 split in Murrieta. San Diego North County, southern Orange County and southern Riverside County are a lot alike, but they don’t really have their own media market. As such, you have three different radio markets: (1) Los Angeles, (2) San Diego and (3) the Inland Empire San Bernardino / Riverside market. If you are in these areas, you can pick up radio stations from all three radio markets and choose what you want to listen to. Television, though, is a little different since the Inland Empire does not have their own television market with local stations so if you are in Temecula, you will get LA stations on cable, but if you go a couple of miles south on the I-15 into Rainbow Valley in San Diego County, you will get all the San Diego television stations. Not sure if there is such a dichotomy of large television markets so close to each other like that where a couple of miles is the difference between receiving LA television stations or San Diego telev