Liberty Garden Fly glitch
The Liberty Garden Fly glitch is a minor glitch in Pokémon Black and White.
Upon visiting Liberty Garden, its Fly dot is filled red, as if it was a location which can be flown to, even though it cannot.
For this reason, it is possible that during development of Pokémon Black and White it was originally possible to Fly there, although it could also simply be nothing more than an oversight.