Jerry Vyse, 21, of Fallowfield, Manchester, decided to show his suport for the campaign aiming to wrest control of the club from current owners the Glazer family.
However, for sporting one of the protesters' distinctive scarves he lost his job.
The movement has adopted the green and gold colours as a reference to the club's origins as Newton Heath, but Vyse soon discovered that his personal protest would not be tolerated.
"I bought the scarf outside of the stadium," the first year anthropolgy student told The Manchester Evening News.
"I told the vendor I would be wearing it to work at Old Trafford for my shift for that evening’s game against AC Milan. He warned me that some staff were sacked on the spot for doing that."
Ironicially perhaps, former United idol David Beckham, playing for Milan that night, picked up and wore one of the green and gold scarves after the game as he applauded the crowd.
Beckham later claimed that he did not know that the scarf was a sign of protest.
Vyse was applauded by many of the fans to whom he served food and drink last week before his employment at Old Trafford was brought to a premature end.
"The supervisor came round and ordered me to remove it [the scarf]," Vyse added.
"This was met with jeers from the United supporters, most of whom had the scarf on themselves.
"When I refused, the supporters cheered. He was then booed when he put the queue on hold to enter the kiosk and request I leave with him because my scarf was ‘anti-Glazer’."
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