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.
Rooms With a View (2) - S10-E8
Factual error: Niles' room is filled with flowers. Flowers are strictly forbidden for cardiology patients because of the high risk of infection. Niles being rich and all that would not change the fact that no flowers are permitted whatsoever - they could kill him.
Factual error: When the barista hands an umbrella to Frasier's guest we can see she is wearing platform flip-flops. Health code in Seattle forbids open-toed footwear for employees in food service establishments, which would include a coffeehouse.
