I recently noticed while watching an MLS match that the referee used a can of white spray paint to mark off ten yards after awarding a free kick. I had noticed the paint can on referees’ uniforms all season, but only after seeing it in use did I realize what it was. Is this a new practice? And is this something that can be utilized by officials in lower level matches?

USSF answer (June 27, 2011):
The International F. A. Board decided at its meeting in March 2011 to allow the use of the vanishing spray paint as a continuing experiment in CONMEBOL (South America), where the proposal originated