I set up all my Discourse user accounts — including this one here — to never send me emails period. My inbox is cluttered enough without any junk that I can discover by visiting the specific Discourse. Doesn’t matter if it is to tell me I have been awarded a badge or for something more useful I do not want email about it.
All I’m saying is that you must respect user’s preferences and if they have Never as the setting for email then that means NEVER.
As an aside I find the whole badges/cheers/etc idea to be purile and especially so for techincal communities.