I can't believe that was stock. It just doesn't make any sense that a BB would be shopped that way. It's not even in the right place if the design called for a liner, but then again, there's lots of stuff in the bike world that doesn't make sense, so why should Trek be an exception.

A well designed weep hole is usually smaller and baffled or shielded so it isn't a primary source of dirt entry. Some of the necest I've seen are hidden under the plastic cable guide which, in turn, is relieved in the back to make a channel.

BTW- IME left side BB and hub bearings seem to fare worse because they're more exposed to spray. Even going back to the days of open cup/cone BBs my left side was always more contaminated than the right. I suspect that the right crank arm spider acts as a sort of shield, while the left arm is perfectly shaped to bounce spray directly toward the spindle clearance.