If server owners really want to help prevent that "race" the config has a very simple solution simply add cobble stone to the list and a cobble gen is useless (though adding moonstone and/or sand) might be needed as well) the only down side of this is that it does make so one of the god things about the recycle goes away; where to throw your spare useless stuff
I think if you're going to do that you would also need to add smoothstone, sand, snowballs, snowblocks, ice, gravel etc. Because all these can be made with a blockbreaker and a simple machine operation too. The effort to remove all this would be so difficult you may as well remove the recycler from crafting.
I was just complaining about this last night. It's not the recyclers, it's the ability to create free cobble with gens. Adding cobble to that list wouldn't be very bright for a server owner.
I'm glad your server hasnt been overcome with snowmen yet then :p Once people on my server realised how much more you can produce with snowmen and blockbreakers compared to cobble generators they went nuts.