NSA dealt with cases of espionage via the introduction of simple electronics into secure areas decades before [1] [2], so awareness of the risk was likely widespread.

The issue here seems to have been that in 1999, it was a relative novelty for random consumer devices to have a recording functionality. Hard to imagine now, but there we are.

[1] https://en.wikipedia.org/wiki/The_Thing_(listening_device)

[2] https://www.cryptomuseum.com/covert/bugs/selectric/index.htm