Revealing mistake: When Stan is at the launderette, a man is shown writing on paper. There is no ink shown on the paper. He's also only writing on one single line and not moving down after finishing the line. (00:01:10)
Continuity mistake: The way the glass is shattered keeps changing between shots when Bullock jumps out of the diner window. (00:19:35)
Factual error: Steve and Roger make a prank phone call to Tony Blair at 4:30 AM GMT during sunset in Virginia (EST/EDT); because of the 5-hour time difference (4 hours during Daylight Savings), it would be 11:30 PM or 12:30 AM in Virginia, which would be nighttime.
Chosen answer: It is just the decision of the creators to do so.
MasterOfAll