Clementine didn't know who these people were and she didn't recognize any of them either.
She didn't know if stating she was in the military would do more harm than good so she kept her mouth shut. Clementine was smart and knew that they would perceive her differently once they knew who she was. For now, she was a harmless girl that was just saved by the military, this perception would help greatly in the interaction that was about to be had.
Samantha was brought there and from the look of things, she wasn't forced either.
Samantha was skeptical when it came to people but she also knew as long as she did what she was told, she would be good.
This has been the key to her survival but there was something different about these men.
They didn't look at her strangely and this allowed her to drop her guard but one could say that seeing the military uniform also put her at ease.