I've just been noticing lately that when I pick the meat on my hand from where my thumb starts rubs up against my bridge pickup. Is this a bad thing? I have a tonepros locking bridge so the pickup is raised maybe a little bit less then half an inch off the guitar body.
Well, in my opinion, just make sure your hand isnt rubbing against the strings, unless you're muting. its the preference of some players to rest their hand against something
If you're serious about having the best technique in order to play as fast as you can, then yes, it's a bad thing and your picking hand shouldn't be touching any part of the guitar.

If you just play casually or aren't a speed demon, you should be fine as long as it doesn't stop you from doing what you want.
as long as your hand isnt fixed and "STUCK" to that one spot on the bridge its fine.

if your just litly barly rubbing part of your hand on the strings its no bit deal...but u cant put no presure on the bridge or your "anchoring". but i do the same thing..it helps mute strings when your sweeping..but u gotta really make sure your pushing down on the strings and your wrist moves. anyway it wants too without those strings bothering it.

if your hand is fixed in one spot and will not move..your anchoring..ull need to slow down and pick ur hand up just lil bit and play slow..but if it just barly rubs the strings and allows your pick to move freely with no restriction then your alright..

u should prolly pratice slow anyway and keep your hand completely off the strings and make sure your not fooling yourself thinking your playing a techquince correct when really your not.