You mean as in being allowed to?
Oh yeah, once they started construction on the garage they HAD to open that lot up for guests. I'm curious as to where the employees park, because it must have been made big enough for that building for a reason.
I don't know if they do it nightly, but on busy nights there is a small shuttle bus that gets you from the Team Disney to the Cirque/Disney Quest area. But honestly, it's not a long walk across the street.