Starring: Calista Flockhart, Melissa Benoist, Mehcad Brooks, David Harewood
Corrected entry: Supergirl has X-ray vision, but never thinks to use it to figure out that Reign is really Samatha Arias under the mask.
Corrected entry: Teenage Kara has pierced ears, even though her skin is supposed to be impenetrable. (00:13:15)
Correction: Magnetic clip-on earrings exist, and can make the sort of dents in her ears which these seem to, due to the strength of magnet involved. Adult Kara also has the same earrings, as seen in the "previously on..." segment.
Continuity mistake: Rick Malverne has handcuffs on when J'onn goes in as his dad. When he figures out it was J'onn, he tells them they have "23 hours and 14 minutes," looks at his watch and the cuffs are gone. (00:21:30 - 00:25:00)
Cat Grant: All four of you standing there doing nothing, you look like the attractive yet non-threatening, racially diverse cast of a CW show.
The Adventures of Supergirl - S2-E1
Trivia: When Cat Grant walks to her office door, she screams out, "Miss Teschmacher!" In Superman and Superman 2, Miss Teschmacher was Lex Luthor's assistant and him screaming her name was his way of getting her to run to him.
Question: Why did they move the show to Vancouver?
Answer: For one, it's usually cheaper to film in Vancouver because of the tax breaks. But all the CW Arrowverse shows (with the exception of "Black Lighting") are/were filmed in Vancouver. So it makes it easier and cheaper for sharing set designs, crossovers, etc ("Black Lightning" filmed in Vancouver during its crossover). Originally "Supergirl" wasn't part of the Arrowverse when it was on CBS, but it was too expensive to produce and wasn't reaching the wider audience the CW shows had. So CBS moved it to its sister company, The CW.
Correction: They have not specified what the mask is made of. It is likely lined with a dense element, such as lead, which Supergirl cannot see through. Just because we've not seen her try, doesn't mean she hasn't.