I was working in a border town in radio back in the 1980s. At one point I handled the music and voiced some spots for a guy in the USA that leased a station in Mexico.
What I recall was the Mexican Government could make stations run PSAs in the quantity the Government determined. For example, a PSA might have to be played every hour for a few weeks. You couldn't refuse. If a station opted to sign off 5 or maybe it was 6 hours before the National program on Sundays they did not have to carry it. I think the national anthem thing was happening then too. I recall one station operator saying stations were supposed to play music created in Mexico. This was when Tejano was getting big and some border stations on the south side of the river played some Tejano. He implied he could get them in trouble. I didn't ask if that was a rule.
At one point, unless specifically allowed to do so, stations in Mexico had to broadcast in the Spanish language. Literally it was a bribe that got the exception. When the Mexico version of the FCC Field Examiner showed up, they got lunch at a nice restaurant and usually a nice shopping spree at the shopping mall on the US side. I am guessing some dollars exchanged hands because they field rep had to grease the palms of his superiors as well. Bribes are part of doing business in Mexico. One owner I knew told me it took about $50,000 to get the license and $30,000 to build plus a few greet and meet trips to accomplish it.
Mexico does not operate like the USA. For example, you go shopping in the border town and park on the street, you put change in the parking meter, then hunt down the local cop on the beat to offer a little cash (then $2-$3) if he'd watch your car and refill the meter in case you don't get back. If you skip this part, the cop might go turn off the meter after you are out of sight and have your car towed especially if the cop thinks you might have a little cash in your pocket. Police have low salaries there. In fact, during one inflationary time police were hocking their guns and radios to make ends meet.
In Mexico, it is the cash in your pocket and who you know that matters. Once a buddy and I were sent across to buy a case of Coronas. As we walk out and start to get in the car, three cars pull up with police and weapons drawn, telling us in proper English to put our hands on our heads. I tell the cop nearest me that my friend, gave his first and last name, needed to be contacted. My friend had said to mention him if I was ever stopped. He was the secretary to the Mayor. The cop asked the name again and then said they were sorry, we were not the people they were looking for. That took about 5 to 10 seconds. They got back in their cars and left. Shaken, scared and overwhelmed by it all, so did we.
Funny thing, at another station, the news director was across the river pulling out of a Pharmacy parking space when a cop blocked him in. The cop came up to his car window and asked if the news director had something for him. The news director said no, so the cop showed his gun. The news director said he had one of those too and it sure would be terrible if something happened to the cop. The cop got back in his car and left. The incident was the lead story on our station the next morning. That was a 'bride' that didn't happen.