An aircraft being in stealth mode or flying under the radar isn't invisible. Those who know have done their DD can see it, can hear it, and can forecast its direction and its likely destination.

However, those who are watching the radar screen only will not notice it.

Synopsys' Terry Ma making a statement in a news release of a small, unknown company will pass more or less unnoticed. The same statement in a Synopsys news release would create a bright green spot on the radar screen.