Other mistake: When Marshall brings the large photo of The Captain into the apartment, he claims he took the photo the last time that The Captain picked up Zoey, but the background of the photo is not the inside of a vehicle.
How I Met Your Mother (2005)
1 other mistake in The Mermaid Theory - chronological order
Starring: Jason Segel, Neil Patrick Harris, Cobie Smulders, Alyson Hannigan, Josh Radnor
Subway Wars - S6-E4
Revealing mistake: When Ted uses his laptop to get directions to the restaurant, Bing shows Los Angeles (where it's filmed) as their current location, instead of NY where the show is set. (00:02:15)
Barney: It's gonna be legen...wait for it...dary!
More trivia for How I Met Your Mother
Question: Has the mother been cast yet? Also, does the film crew know who the mother is already?
Chosen answer: She was finally shown at the very end of the last episode of season 8, continuing into season 9. The actor's name is Cristin Milioti: http://www.imdb.com/name/nm2129662/.
Suggested correction: Depending on the location settings on his laptop, they could be giving a false reading. My laptop shows I'm in Cardiff Wales while in fact I'm nowhere near.
Ssiscool ★
The show was actually filmed on a film set in Los Angeles which is probably why the laptop says Los Angeles as the current location. This most probably slipped past the editing crew.