Most of these guideline above do not enhance reliability. The object is not to make your code look like it came from an obfuscated C contest.
I put the open curly brace on its own line. Not that it needs to be, but because it enhances the readability of the block of code contained.
Readability == Less bugs
One exit from subroutines/functions/methods makes it easier to debug. Definition at the top, makes it easy to find variable type and initialization, instead if hunting through all the code trying to find the definition. Though a good IDE will handle most of that for you.
All this saves programmer time and makes for easier maintenance.
The OP says "unnecessary code -- e.g., variable declarations..." who doesn't declare their variables. I would hate to debug that code.
Also, who considers error handling, unnecessary code. Critical or not, the programmer should catch and handle every type of error he can. It's called robustness.
All this "unnecessary code" has a purpose, enhanced readability, less bugs, faster debugging, easier maintenance, stability. All these young bucks could stand to take a lessen or two from the grey beards.