I see that escape velocity on 67P/Churyumov–Gerasimenko is 0.64 m/s. (Contrast Earth's 11,186 m/s.) With such light gravity I imagine any material kicked up would take hours to land, or orbit indefinitely. The thing seems covered in sand and fine particles, in line with the rubble pile model of cometary nuclei.
Have precautions been taken with the landing of Philae and harpooning its anchor to lessen kicking up dust? Are we likely to see landing dust in photographs?