RTFL
"The difficulty in resolving closely integrated black and white images on non-color television receivers was one of the primary reasons NFL games were not regularly televised until the mid-1960s, when sales of color TV sets started to outstrip those of black-and-white models. When black-and-white television predominated in the nation's living rooms,
football games were too often disrupted when players ran into the referees, whose black-and-white striped uniform tops made them nearly invisible to onlookers. Likewise, Johnny Cash's famous televised live concert performance at California's Folsom Prison in January 1968 proved disastrous when several inmates wearing the traditional black and white prisoner's garb slipped unnoticed past guards, who had been provided only black and white monitors with which to view the proceedings."
EDIT:
Though the bolded bit makes no sense.
Why would the
players not be able to see the referees?
*goes and does some research*
Dang it!! I was had
snopes.com: False Authority
"Everything in this section is a spoof.
Mister Ed was no more a zebra [...]"