wolfen68, I am as anal retentive as anyone when it comes to remaining totally scentfree. EXCEPT for the beechnut I always chew while hunting.
I have yet to see a bad reaction from a deer, even when they get directly under me. And yes I spit on the ground. Take a pretty tough stomach not to spit loose leaf tobacco!
Anyway, I have filmed probably 15 P&Y bucks within 20 yards while chewing.
Killed 3 P&Y bucks while chewing.
Was at full draw on a 175 class buck last year while chewing, at a distance of 8 yards! Just never got the right shot.

Maybe I am lucky, but I truly believe that chewing tobacco does not bother them. (at least my brand, anyway)