On a server where flying is disabled, riding a NoGravity Boat will kick the player from the server saying flying is disabled.

What I expected to happen
Enjoy a plesant flying boat ride

What actually happened
I was kicked from the server with the message "flying is not enabled on this server"

Steps to reproduce
Join a server with flight disabled
Summon a NoGravity boat.

/summon boat ~ ~ ~ {NoGravity:1}

Go ride around in the boat for a bit.