im not sure about that one..i guess professionals dont have to worry about it because they have such good stuff and good guitar techs...or they just get a new one...but for us people with one or two guitars....hmmmm
im not sure to tell you the truth...

but if you unscrew the cover plate in the back of your guitar you might find the springs that hold your wammy bar in place...so when you push the bar forward..it stretches the strings placing them in tension..and the screws that hold the springs in place....i assume would be causing the creaking noise in the wood?

if it's of concern to you...just practice on the more finesse type of playing with the wammy bar...
i still find it very cool when an artist can have such control over that bar...
good luck
-G