Madison Square Garden employees are being cut off from the outside world while setting things up for Taylor Swift and Travis Kelce 's mega-bash this week ... because they're not allowed to have their phones while they work. Employees who work in event production for MSG tell us ... they can't have their phones during the shift, and while they haven't been told why, it's presumably so they can't take pictures of the setup. We're also told employees are wearing wrist bands -- which is out of the