go unobserved
pass unobserved

They went door to door through the building, she said, spraying brown paint to block the keyholes so they could pass unobserved.

Further, irregularity of this kind would be particularly unlikely to pass unobserved, since contrast makes observation easy.

That means more men than could ever pass unobserved through the mazes.

Elis had not removed himself far enough to pass unobserved, she felt a presence close, and turned her head sharply.

All the little world was so absorbed in its own interests, that the strangers passed unobserved amid the laborious inhabitants.

To pass unobserved within the barracks and the keep.

From the same cause many interesting animals pass unobserved, although they are very numerous.

Dusk was already settling and the maneuver would pass unobserved.

To allow it to pass unobserved seemed somehow to violate something very sacred.

Yet, you were in this room for a considerable length of time, and the clothing passed unobserved, even by you-a man usually quite observant.