I tried what was said in the thread and couldn't manage to allow my player to move. If the player is suddenly very jumpy then chances are they still have their keyboard open, which causes a huge drop in fps. However, having the keyboard open means obscuring the keys for movement. Also, even if you close the keyboard and leave the chat bar open(by hitting the down key on the keyboard instead of done), you can not tap or change focus at all to the game. Maybe they are using an external keyboard(bluetooth) or such, for which I can not test.

Also if the root of the problems is the in-game keyboard, which it probably is, it is not something a scripter can deal with. We have absolutely no access to the keyboard at all.