Re: Can Treble Bleeds Suck Bass/Fullness on 10?
My understanding is that there's still some resistance through a typical pot even at the end of its travel- generally around 1% of its max value, I think. Different value pots can make a guitar sound different even when they're maxed. The exception would be no-load pots, designed to fully short out at the end of their travel, effectively removing them from the circuit.
I think it's not inconceivable that a bleed cap might still pass enough treble for the guitar to be slightly brighter when the volume pot is on full, especially with the higher value pots used in humbucker guitars. (For a 500K pot that 1% is still 5000Ω, vs zero for a cap... at audible frequencies anyway.) I doubt this would affect the low end at all. Still, if the sound is a little bit brighter, it might easily seem as if there's a bit less bass.
Then again, I'm no expert- maybe there's something going on there that we're missing and the low end actually is different now.
As gregory said, though, perception can be tricky and that's certainly true when it comes to tone. Just knowing something's been altered can predispose us to expect a change. And when you're looking for a difference it's easier to find one, whether it's real or not.
Studies have shown that people can perceive portions of the same food to taste differently when they see different colors. It might be interesting to see a study done using a guitar with switchable tops in various colors. If the test subjects believed there were several guitars, would the red one seem to sound different from the blue one or the yellow or silver one? I don't know. But it wouldn't surprise me if it did.