Oh, I see what you meant by "you can't." I thought you meant, one can't pull on a string, while it's on a bass (as in, for example, stretching it) to anything close to the tensile strength of a tuning machine... and I thought (and posted), sure you can, just pull on it, the pitch raises, ipso facto proof of increased tension to the same degree as a half-dozen turns on the tuning machine key. I didn't realize you meant with bare hands!
As far as the second part, I still say, when you pull a string away from the neck, you are increasing the tension of the string, and not flexing the neck much (certainly not any more than if you tuned the string to a higher pitch equal to the same amount of tension, and certainly not MORE than you're tightening the string).
As far as affecting the tone of a string by pulling on it, are we talking about affecting tone, or pitch? I think you meant pitch but I'm not sure, just wanted to clarify.
As far as your bet; I'll pass, knowing you meant with your bare hands. However, if you're talking about we both start with a bass strung-up, and I pull on the .105 E string (off the fretboard) and you tune your .105 E string up with the tuning machine, and whoever breaks a string first wins $100, yeah, I'll take that bet!
