Factual error: Considering how the sisters and Cole every now and then - especially during seasons 3-5 - find themselves in some churchyard or cemetery, it should be noted that there are no such places in San Francisco! Except for the original one at an old nunnery, from before the city was founded, and the Presidio Military Churchyard, all graves were moved in the first half of the 20th Century to the cemeteries at Colma, a few miles south of SF. This was done due to the sanitary risks in case of earthquakes, and the lack of space for churchyards downtown.
Factual error: Throughout season 8 the members of the Triad wore a pentagrams on their gowns that would alternate from the point being up and point being down. They should only be wearing a pentagram with the point facing down. Pentagrams with the point facing up is the symbol for practitioners of white (good) magic while those who practice black (evil) magic is symbolized by the point facing down.
Factual error: Numerous times in the establishing shots of San Francisco, the Embarcadero Freeway is visible. While the bridge did run along the San Francisco Bay, it was demolished in 1991 - seven years before the series even started.
Thank You for Not Morphing - S1-E3
Factual error: At the end of the episode the girls are waiting for Victor. He doesn't show up but sends a package containing a home movie. As they are watching it, they see Christmas when they are little girls. Phoebe can't be more than 4 yrs old, 5 at the most. Since she was born in 1975 that would make the home movie take place in approx 1980, but she gets a Wedding Day Barbie, which didn't come out until 1996.
Factual error: In the opening scene in Salem, Melinda Warren is going to be burned at the stake. But in the real Salem trials, no one was burned; all of the people convicted of witchcraft were hanged.
Factual error: Melinda Warren says that after Matthew turned her in to the council, she was burned at the stake for being a witch, except witches were not burned at the stake, they were hanged.
Factual error: Little Piper (from 1975) has blue eyes. She should have brown eyes, like present day Piper.
Factual error: Phoebe is going to be burned at the stake for witchcraft like they're starting the Salem witch trials again, but witches weren't burned, they were hanged.
Factual error: During the ritual, we can see that the snake that is magically transformed into a man is a milk snake. But it's not poisonous, it's a colubrid. The creators apparently wanted to use its resemblance to a poisonous coral snake, which is an elapid. (00:02:35)
Sight Unseen - S3-E5
Factual error: When developing a photo it's first put into a developer chemical, which shows the picture up, then a stop, which stops it from developing anymore, then a fix which "sets" the photo. But in the basement, Prue puts the exposed photo into a tray with chemicals in it where it starts to develop, then into a second tray where it develops fully.
Sight Unseen - S3-E5
Factual error: In the scene where the invisible demon is entering Cole's office, the courthouse shown before the elevator is a New York City courthouse, not San Fransisco. It's confirmed by the presence of a NYC Taxi.
A Paige from the Past - S4-E10
Factual error: On the wall of Paige's bedroom when she was a teenager is a Metallica poster for "Garage Inc.", a CD not released until 1998 although Piper later says that Paige has gone back to 1994. (00:16:05)
A Paige from the Past - S4-E10
Factual error: When we see Paige's 1994 bedroom, she has what appears to be a Bride of Chucky doll. The movie "Bride of Chucky" wasn't released until 1998. (00:16:20)
Factual error: When Phoebe was telling Paige that the energy ball did not come from the other house, Paige says she saw it come through the window. She could not have seen it because she was in the other room and the door to Richard's dad's office was closed.
Factual error: When Leo shows Piper, Phoebe, and Chris the "warning label" on the genie bottle, he turns the bottle clockwise, reading from left to right. Arabic is read from right to left.
Answer: That was a mistake in the series.
Also, the episode is called 'Babies First Demon' and this alone tells us that it's Wyatt's first time in the field (so to speak) and as the sisters say, they've done a good job of clearing up their own magical messes so far. Nobody really knows how advanced Wyatt's powers are, or will become. That's why the cleaners appear, to nip things in the bud. The Cleaners didn't want to chance that the sisters could clean Wyatt's magic up, just incase they couldn't. Therefore intervening themselves, just in case.