At 100 MHz I am unsure if transmitter even exists that can could cause harm indirectly via RF exposure. The FCC has very tight guidelines for FM transmitters at this frequency. This is just an abundance of caution.

The actual story as presented here is obviously fake: "I replaced the 100W FM transmitter on our college radio tower and got in front of the emitter beam for like 10 seconds and my head rung for a week". It's unlikely, but possible that the transmitter is mounted on the tower. In practice, no one does this. They use coax at ~100 MHz since it is so cheap and easy. Let's just assume the transmitter is mounted on the tower. The power cutoff is going to be at the bottom of the tower. You turn it off beforehand because you don't want to get electrocuted inadvertently. You don't disconnect equipment while energized. The phrase 'emitter beam' is also a dead giveaway. That phrase is only used in particle accelerator and other radiation sources.

Walking around a modern suburban development devoid of people, houses, pets, etc. would be at least unusual in the feeling. The spaces are intentionally designed to put people and their things within obvious boundaries. With the boundaries still there but lacking the things within them it becomes quite a different experience.

Like many things throughout history, I strongly suspect it means whatever the author means.