Royal Mail urged excited fans to leave the painting of postboxes to their staff after one was given a bronze makeover in honour of the British women's hockey team.
The postbox, in midfielder Georgie Twigg's home town of Doddington, Lincolnshire, was repainted after Britain took bronze with a 3-1 win over New Zealand in the third-place play-off on Friday.
It comes after Royal Mail engineers have been marking the achievements of Britain's gold medal-winning athletes by painting postboxes in their home towns gold.
But the firm vowed to repaint this one red as soon as possible.
A Royal Mail spokeswoman said: "We understand the sentiment, and congratulate the women's hockey team on their achievement.
"However we'd rather people left the painting of postboxes to us.
"We are liaising with our engineers to ensure that it is repainted red as soon as possible."
The image of the bronze postbox was retweeted by Twigg after she was sent a copy on Twitter along with the message: "@georgietwigg, Village postbox, amazing support from your local Lincolnshire Village of Doddington".
Twigg capped her Olympic debut with the bronze medal - only the second ever won by the women's team - and admitted it was an experience she would remember for the rest of her life.
"I'm absolutely thrilled and I can't quite believe it," the 21-year-old said.
"It has been absolutely amazing. The crowds have been out of this world. I have absolutely loved every second of it and to come away with a bronze medal I'm delighted."
Hampshire Police said they arrested a 54-year-old man for spray-painting a postbox in Lymington, where Olympic sailor Ben Ainslie lives.
Rob Smith told the BBC he painted the postbox in Lymington High Street gold to mark Ainslie's latest gold medal - his fourth.
He said he thought it was "madness" that an official postbox had only been painted gold in Cornwall, where Ainslie grew up.
He told the BBC: "He's lived here for around 15 years, all of Lymington believes that the post office made the wrong choice in painting one down in Cornwall - give him two.
"I did it because I'm a passionate sportsman, I think the Olympics have been brilliant. Ben's achievements have been outstanding."
A police spokesman said: "A 54-year-old man has been arrested after a Royal Mail postbox in Lymington was spray-painted during the early hours of this morning."
He added that the man has been released on bail while officers liaise with Royal Mail