My LEAF gets the car wash treatment about every 3-5 weeks so over two years of ownership it has had lots of mechanical car washes. These have been touchless, soft touch, and rotating brush style car washes, probably an equal number of all 3. So far, no external damage is visible, nothing is loose, and I can't see any leaks.
That said, the roof antenna, according the the Owner's Manual, is for satellite radio, which I do not subscribe to. Also, on page 4-9 of the Nav Manual, there is this:
ROOF ANTENNA
Removing antenna
You can remove the antenna if necessary.
Hold the bottom of the antenna and remove by turning counterclockwise.
There is also a caution to do this when entering a car wash.