F-Fan, you can have contamination and it won't show in the reservoir for a while since there isn't any recirculation to speak of. You can also have a leak and not have any contamination due to the way the system self pressurizes due to the fluid expanding when it heats up.
A bunch of the B-3 owners I know tell me they use some fluid during the season. While I'm envious of the folks who have "tight" drives, I don't lose any sleep over the little bit I have to add every few times out either...it's always been water free when I've drained it.
Exactly my experiences as well.
DaveR once posted on here about the 2 way seal on a B3 drive. The gist was that it's possible foe it to let oil out, but not water in. Since I add oil to mine periodically, but have never had water contamination, I have to believe he's right on the money.
That said 1 qt in 35 engine hours seems like a lot. Unless the drive wasn't properly refilled when serviced.