Hopefully this isn't on that kind of hair-trigger that shoots down civilian airliners by mistake. It's happened literally dozens of times [0], so it's hard to believe any kind of blanket "this can't possibly happen because..." logic.
Seems to be particularly likely to happen in panicky situations, or when someone has something to prove. E.g., the Soviet-American tensions surrounding an American spy plane, a RC-135, were a factor in the Soviets shooting down KAL-007 (they thought it was the RC-135) [1].
Protocol is to visually identify the target. In the case of an airliner, they try to make visual contact with the pilots if they don’t respond by radio. There are visual verification methods commercial pilots are trained on.
And airliners have transponders and flight plans. If a civilian plane stopped talking to ATC, the Air Force is likely already involved.
Additionally, we’re not on a high-alert war footing like during the Cold War. As far as I know, we don’t have hostile military aircraft routinely flying with transponders off on our coasts.
Even if we did, I’m pretty sure the larger military radar systems that would be used to track this stuff can read transponders and separate out which plane is which.
Seems to be particularly likely to happen in panicky situations, or when someone has something to prove. E.g., the Soviet-American tensions surrounding an American spy plane, a RC-135, were a factor in the Soviets shooting down KAL-007 (they thought it was the RC-135) [1].
[0] https://en.wikipedia.org/wiki/List_of_airliner_shootdown_inc...
[1] https://en.wikipedia.org/wiki/Korean_Air_Lines_Flight_007