When Shawn is trying to get a job at the Mirror, he impresses editor Phil Pritikin by deducing that the editor is left-handed. However, in several scenes, Pritikin can be seen writing with his right hand.
When Chief Vick explains about the homeless man dying, she is holding the folder open in both hands. In the next shot it is suddenly closed and she holds it only in her right hand.
Uncle Burton tears the postcard in half, then after a cut it's whole and he tears it in half again.
When they see off Gus's uncle, the sign on the side of their office says Santa Barbara Museum and Archive. But even if they shared that space, they wouldn't be at the first floor.
Shawn and Gus try throughout the whole case to make sure Uncle Burton doesn't find out that Gus isn't really psychic, however all he (or anyone else in Gus' family for that matter) would need to do is to check the papers to see that Shawn is the one who gets all the acclaim for being psychic. If Gus' family really is as proud of him being a psychic detective as he makes them out to be, it makes no sense that they wouldn't have checked the papers by now.