The sole term of calling someone a "Bucket Kid" mean that you are describing that person as a BK, lowlife, and someone who just fucks up everything you do. Not only does a Bucket Kid do all that, but the 'Kid' also puts down everything you have achieved, worked for, and gotten all due to time. Basically this is a person you do not want to be.
The term was made and used by an elite group of gamers associated with the Halo 3 team Love and Cuddles. Sausage x J and uShift came up with the term.
"Ah f*ck, that fucking bucket kid cost me the killtrocity."
"Watch out for those Reflex Bucket Kids"