Why not? A dozen or so companies I have followed, were delisted while halted. None of them reported earnings. All of them except one are trading on the pink sheets. I do remember some of them did not have quotation for a while but I didn't know they were grey temporarily.
Hell, even RINO is trading on the pink sheets. I believe they started this mess. And CCME was also before it was revoked, if I remember correctly. So what exactly is it with the grey market?