Other mistake: The guy who plays Clive in this episode has one of the most appalling accents I have heard. He's apparently from Manchester, but sounds like a sort of cockney South African. His accent slips around all the time; it's very poor. I wouldn't normally submit it, but his is so shockingly bad I doubt anyone would be fooled into thinking he was British.
Suggested correction: I think this may have been deliberate. The episode is almost meant to be ridiculous, with the characters quickly churning out lies on the spur of the moment, and everyone supporting the fake family story without objection.
Other mistake: When the power outage occurs, Daphne claims she can't cook the steaks, however, the cook top in the kitchen is gas. They have matches as shown by them lighting the hurricane lamps.
Suggested correction: In episode 6:02, Frasier's Curse, Niles finds Frasier's head in the stove and is worried. Frasier responses "I was cleaning it, Niles. It's electric" The matches seen in episode 2:24 were more likely used for candles (like for Frasier's bath), not the oven, because it's electric.
The range is gas burning. You can see the grates and burners indicative of a gas cook-top. The comment regarding the matches wasn't used as proof the range is gas, but merely to point out they had the ability to light the gas cook-top (to avoid someone correcting the mistake by saying maybe they had no matches). The mistake is valid. In s06e02, the cook-top is still gas and one may want to submit a character mistake for that episode because Frasier says it's electric when we see it's gas. However, if one submits the mistake, be prepared for someone to correct the mistake by pointing out that dual fuel ranges exist, so the oven could be electric and cook-top gas, Frasier has an electric oven and gas stove, or Frasier was simply lying.
Factual error: There are many factors concerning Niles' post-operative state which are very inaccurate. After open heart surgery it takes at least three months for the chest bone to heal, Niles would not be able to drive a car for weeks, nor would he be able to lift or twist which he does on the show. Also, he doesn't sport a scar. Your chest bone begins very high up, just below your neck, his scar should have been visible on numerous occasions.
Suggested correction: He has a scar in season 11 episode 8. When he's naked in the cafe. A scar just like my dads from heart surgery.
While this mistake points out many different factors, I don't think this should qualify as a valid correction. The mistake is saying in season 10 he doesn't have a visible scar when he should and the correction points to seeing a scar a third of the way into season 11.
Continuity mistake: Blaine sticks the pin in his leg and doesn't remove it, yet after a few shots it's gone.
Suggested correction: The pin is present until Daphne removes it, but in each shot the pin is rotated without anyone touching it. In some shots, it is difficult to see because it is longways on, but it is there.
Continuity mistake: At the end of 3-10 in the airport with Kate, Frasier says that he has an allergic reaction to cats but here he cat sits for Mr. Bottomsly.
Suggested correction: This has been addressed in the Questions section. Frasier is apparently choosing to deal with his allergies, in order help the cat's owner. It's also possible for allergies to be triggered by one cat, but not another. It depends on the amount of dander that the particular cat produces, and the level of Fel D. 1, a protein in their saliva.
