I don't know how 'gray' the area is. My Obligations under my Consumer Proposal are statutes in law...that clearly state that I must declare and turn over all credit cards in my possession, in my name. There is no grey area in that wording. Even if the cards are US or Canadian or other foreign...they are credit cards with my name on them, and in my possession. What if my mother had some of my credit cards...well....they're not in my possession...but they do have my name on them!!!

Perhaps, that's the grey area.
Some folks have Trustee's who refuse to allow them to get secured credit cards, I've read about that. One sometimes needs a letter from a Trustee to get a secured credit card. I don't know how my Trustee thinks about this, I didn't ask him.
I do know that I'm allowed to have a prepaid Mastercard. I do have one, and I have used it. I asked first, and it doesn't break any of my CP rules.
It would be nice if someone with expert knowledge could give more insight into that 'rule'...!