Even though Walcott apologised for his dive straight after the 1-1 draw, manager Simon Grayson reckons Leeds' notoriously partisan fans are in no mood to forgive and forget.
Grayson said: "Theo will have learned his lesson and probably won't do the same thing again.
"But, if he plays in the replay, our fans will make their feelings known. I know Arsenal have played on the big stage many times and also have players who have appeared in World Cup finals.
"But, maybe, this will be a bit different because the Elland Road crowd is very vocal and extremely passionate.
"There will be a full house of just under 40,000 but, sometimes, they can make it feel like there are 60-70,000 in the stadium.
"I am not sure if many of the Arsenal players will be aware of what the atmosphere is like at a full Elland Road.
"But they certainly will be about five or six minutes before kick-off when they come out of the tunnel.
"Our fans are not woodwork fans. They don't simply come out when it's a big game.
"They have travelled in numbers over recent years to Hereford and other little places like that."