Ahh, I see what you mean. Yeah, that works if you're gonna completely give up on the whole 'making it hard for someone to share the codes' thing

There isn't any good way of making it hard for someone to share the codes unless you're going to set up an Orwellian panopticon that tracks where everybody is using them, and since that is totally unacceptable and half measures are uselessly ineffective, it's reasonable to just accept that codes are going to be shared.