“Many people within the nuclear industry thought this mistake was the stupidest act in refueling history. It is, at worst, the second stupidest act. After … the operator stopped … was righted and moved away from … But, the yellow and magenta rope was left tied to the railing and to the board. When workers later …, it once again … The second toppling dropped the remainder of the 86 missing tags into the spent fuel pool. The second episode out-stupids the first event.”
http://allthingsnuclear.org/fission-stories-70-tag-youre-it/