As told to me about 1980 or so, there is an FCC Rule that it is illegal to produce or cause to be produced any program for a foreign radio station without FCC approval. While they cannot enforce it because they must be able to prove it is happening if done manually as we were doing (recording commercials here and taking the carts to Mexico to the studio) the FCC would simply not renew the 3rd class license I needed to work radio. Such a rule may no longer be in place or changed to fit current times.
The FCC can act over any form of communication they license. In this case, the way the signal gets from the USA to Mexico. Likewise, in Eagle Pass, Texas a Piedras Negras FM decided to go English Top 40 with studios in the USA. They used the Cable TV system to get the signal across the river. When the GM at my station complained to the FCC, the cable TV company dropped the Piedras Negras station.
The FCC can act over any form of communication they license. In this case, the way the signal gets from the USA to Mexico. Likewise, in Eagle Pass, Texas a Piedras Negras FM decided to go English Top 40 with studios in the USA. They used the Cable TV system to get the signal across the river. When the GM at my station complained to the FCC, the cable TV company dropped the Piedras Negras station.