Fallout: New Vegas Message Board  

It's fine to use as long as it's off when you save.

The cheat itself does mess with some characteristics when on: you become a child to the environment and can't 'activate' things, and your scale is set incorrectly.

So remember! Turn it off before you save, otherwise use the console to shrink yourself! (Check out how nice and big you are with external camera if you forgot!)

Also, if you find yourself in this situation, you can also load a prior save (obviously where that cheat isn't activiated) and then re-load your current save and everything should be ok, at least that worked for me.