I am interested in this idea, but I instead decided to improve the way the module responds to packets. I made a module that displays the packet type and its parameters in chat to get an idea of how an AFK player sends movement packets, and that way I made FreeCam module behave the same way.
It ended up not being a good idea, so I tried your method and here are the results:
It's a great idea, because you don't have to modify packets. The only small thing I have noticed is that you have to (at least from the way I coded it) detect if buttons are pressed with InputUtils.isKeyPressed(mc.window.handle, mc.options.forwardKey.boundKey.code instead of mc.options.forwardKey.isPressed for example.
EDIT: Found a completely new method, which doesn't require detecting button presses with InputUtils, basically nothing related to it anymore.