In the episode where the Plain White T's perform, you see Carly, Freddie, Spencer, and Sam sitting in the car while the band is performing. The car seat, however, is created by Spencer in a later episode, in which the iCarly team meets an obsessive fan.
Toward the end, Nevel is mocking iCarly on a video camera while streaming directly to their site, which is presumably connected to a network through his computer. When the military agents arrive, they confiscate two desktop towers and other various equipment; while this is happening, and Morgan picks up the standalone camera to film Nevel, the video data stream continues to show up on iCarly. How is that possible when the camera is not connected to anything, especially without a computer?
Carly and Spencer are visited my their father's friend/co-worker, Colonel Morgan. However, earlier in the series Carly complains to her grandfather: "What does dad know? He is in the Navy in a submarine."
There is no ranking title of a Colonel in the Navy, so how does Colonel Morgan know the kids father?
When breaking into Nevel's house Freddie lowers himself down from the ceiling. However in order to do this Freddie would have to get into the house, attach something to the ceiling and raise himself up then lower himself again.