Alright, so I have three profiles on my XBOX. One is mine, which currently has an Gold membership. The other two (my girlfriend’s and a guest profile) have never even been connected to silver.
So today, I logged on to the guest profile to unlock some of the armor (it’s still a Private), but I was not able to earn a single credit in either campaign or firefight. I did a quick test on my girlfriend’s profile, and the same thing happened. I tried my profile, and I was able to earn credits normally, and I haven’t ever gotten any messages telling me I was banned or anything like that, even though I can’t see that carrying over to the offline profiles if I had.
They also have not come anywhere near the credit limit today (in fact the guest profile hasn’t even been touched for weeks). And again, neither of them has ever been connected to XBOX Live. What could be the problem?