Shame on the flight instructor who wrote a letter that attempted to scare people.
There are two kinds of airports in this country -- those with towers and those without. Even airports with towers are not always staffed 24/7, so they operate as "non-towered" sometimes. At airports without towers, pilots (and fuel, fire, and maintenance vehicles) follow standard procedures, including standard arrival and departure patterns. Any pilot knows that airports without towers usually have radar approach control information from off-site facilities. And he should also know that airports have common traffic advisory frequencies to report their positions to other aircraft. The standard for any licensed pilot is "see and be seen."
There are about 5,000 airports in this country; only about 500 have towers. Have you seen a headline lately about two aircraft hitting each other, either on the ground or in the air, at an airport without a tower? Of course not because pilots in this country are the best in the world, and they know that when there is no separation provided by a tower, it becomes their responsibility to avoid other aircraft.
The contract tower program costs $100 million a year. Closing the tower at Hilton Head Island Airport most certainly does not compromise safety; the U.S. is without peer in the world when it comes to safety. It is irresponsible to scare people like this.