I don't think the Supreme Court ruling draws this conclusion. All it contends is that an individual cannot be charged of theft if the individual did not know that they were stealing in the first place. The ruling leaves the door open to charge the individual with a different crime (failure to comply with a warrant) or even civil proceedings.

You are making a "if I own the wallet, I also own its contents" argument. It doesn't fly unfortunately, and for that matter has never flown. Possession isn't the same as ownership. This is even more so true if you have knowledge of the source of the contents. How else would we catch thieves if it were?