As Melinda puts her seat belt on and grabs the steering wheel, it's under her left arm. In the next shot, just after backing out of the driveway and without any indication of moving her arm, the seat belt is over her left shoulder like it's supposed to be.
In the series, characters often state the importance of keeping Melinda's ability to speak with ghosts away from public knowledge, yet Melinda and Andrea discuss it openly in front of two nameless handymen hauling collectibles for their auction. Unless the men are deaf or can't easily understand English (of which there is no indication), the secret should be blown by this, but isn't.