Pokémon Black & White (be warned: spoilers)

[GrooveMan.exe]

Being able to forget HMs on the fly can accidentally strand you. What if you went to like, Sootopolis City, and got rid of your only 'Mon with Dive or Fly. While you can get out of such a situation (much easier now than in RBY), it's a pain. As such, the Move Deleters are located to you can fish for Surfing 'mon, or a mon that learns Cut or Fly so you can access other areas.

You make a good point there.

Well seeing as HMs never go away, you can reteach ti fly or dive if needed.

In RBY I traded over a Charmander with Cut so I could do the Vermillion City scenario without having the ship leave (So I could try out the Mew/Truck thing) I eventually had to trade it back.

It's entirely possible. It's bad game design to not account for measures that are possible; people will try and break a game in many strange ways.