When Carly is cleaning out her locker, Carly puts a book into the box that Freddie is holding then says "I don't see how we are going to do iCarly any more" - then in the next shot Carly has a sheaf of papers in her right hand that has appeared out of nowhere.
When Carly is cleaning out her locker, Sam's locker is closed. Sam begins to pace. She walks down past her now open locker, but when she comes back to Carly, her locker is closed again.
When Carly, Sam, Freddie and Granddad enter the elevator to leave for Yakima, Carly, Sam and Granddad each have a suitcase on wheels while Freddie is carrying a red bag with handles, however when they reach the lobby Freddie is no longer carrying the red bag.
Carly's grandfather states that it has taken him 90 minutes arrive. Later he reveals that he has come from Yakima. The shows location is based in Seattle so on a good day it would have been 2 1/2 hours to make that trip - assuming the trip was uneventful.
Grandfather Shay would have zero authority to take Carly from Spencer. The process would've involved a legal investigation as well as a court hearing. Even if the court found Spencer unfit to take care of Carly, Shay would not have the rights or qualifications to take her. Carly would have most likely been sent to foster care.
After Carly's Granddad gives her the coupon for the Groovy Smoothie she leaves immediately, and it is broad daylight outside. When she returns after only half an hour it is completely dark outside. Response: Day can break into night quickly, especially if she left just before nightfall.
On Spencer's fan of hammers, each hammer is attached to the fan with two screws. After the one hammer flies off, the two screws that were securing it are still in place on the fan. Thus the hammer that flew off should have two large holes in the handle where the screws pulled through it, or, more likely, the hammer handle would be split up the middle. However the hammer that gets stuck in the wall has no sign of damage to the handle, indicating that it was never actually attached to the fan. As well, all the hammers are facing forward, but the hammer that flies off goes in the wall backward.
It is unknown how Carly's granddad knows that Carly almost got hit by a hammer, because in the shot before, Freddie with the camera went down to the floor, thus not putting the camera on Carly.
After the fire, a fireman compliments Spencer on his chicken stir-fry. However Spencer never did cut up the chicken and put it into the wok, so the fireman shouldn't be able to know it was chicken stir-fry.
Yakima is pronounced "Yak-i-MAW", not "Yak-i-MUH" as it is said many times throughout the episode. Anyone who lives there, or in the state of Washington for that matter, would not pronounce it like in this episode.
Asthma inhalers generally have a shelf-life of about two years, so if Spencer had kept Carly's inhaler since she was seven, it would be long past the expiry date and should be discarded.