Well... to be really, really, really strict.... Removing some code will actually make it run "a little" faster. Because at least the "if" is executed, and if you remove that, you are getting one instruction off.
Doing some testing on my server... if I remove that code, I get a performance gain of 0.00002 seconds, that means, after the 50,000 visitor, I get one second worth of better performance!
What I am trying to say is that, unless you have more than 50,000 visitors per
minute. Don't bother doing this.....
And... as it has been said, none of this has any effect on bandwidth. The size of the scripts is totally different to the size of the generated page sent to the user.