Quick update. The previously piled up ghost bikes have been put back up at their original locations. They have laminated tags from the District Department of Transportation (pictured) saying the bikes will be removed in 10 days. The original artist, Legba Carrefour was not involved in the clean-up.
@ScienceClub confirms DDOT personnel were on the scene putting the tags on the bikes.
To clarify my earlier post from today, the Washington Area Bicyclist Association was not responsible for the ghost bikes. Their offices are located nearby, and they had been involved with the original ghost bike display and worked with Alice Swanson's family.