If you pour your carbonation mixture into the bottling bucket then siphon your beer into your bucket it makes it much tougher to have some bottle bombs. If you pour your carb. mixture into your carboy and stir...chance for oxidation is there...
This brings up another point in the quest for sanitation...
My other hobby is serious photography. I have to wear a mask when I clean my digi-cam SLR's sensor...why...because simply breathing spews out tiny tiny particles of saliva from the mouth...yea just breathing. And the particles collect on the sensor and you can see them (trust me) on your photos.
So if breathing has an effect in that regard, simply breathing over your cooled wort/beer is potentially contaminating your batch.
Another thing is your own hair. You should wear a hat or *gasp* hairnet when dealing with your beer/cooled wort...a single strand of hair could be contaminating.
Here's another minor issue. If you cool your wort on the stove, that cooling process also goes to cool your fan/hood above your stove...and if you get condensation and a drip goes into your cooling wort....yikes.
So, all kinds of stuff to go wrong.