How are mass-produced maraschino cherries pitted? I looked on wikipedia, but it doesn't mention much about pitting.
I'm going to assume you're talking about the "whole fruit" style and not the "halved" style.
It depends on the producer and variety of cherry, but the cherries that I've seen are pitted in two different ways: in a similar way to olives and simply "brute force" pitted.
Like an olive:
The cherry is centered over a round(circular or elliptical) cutter and then a blade(you've seen the cute "X" shape at the bottom of an olive) pushes the cherry onto and the pit through the cutter.
Since most cherry pits are "free"(they don't cling very hard to the pit) it is possible to simply center the cherry over a hole and press out the pit with a dowel or rod. The pit simply "squirts" out and the skin is split a little and the flesh on the opposite side is bruised a bit. This results in a cherry that looks more "whole" and retains more flesh and sometimes you can barely tell where the pit left the fruit.
However, like all industrial processes this can be done many different ways up to and including by hand depending on the producer and/or target cost/quality of the final product.