Dont really understand why proof of mailing is so important. Its just a reciept from the post office that could be from anything. It doesnt say on the reciept what you mailed. So you could go mail anything certified mail and keep the reciept, or just copy someone elses.
Not exactly correct. The reciept is linked to the address you mailed it to. So yes, you could mail a blank envelope to the CDPHE but I doubt most people would bother. Granted a dispensary would have no way of knowing if the proof of reciept was actually to CDPHE unless they tracked it online, but it is to cover their ass that the patient has done everything according to hoyle.

There will always be methods of abuse in any system. This one is no different. Ofcourse, the more difficult they make getting "legal" the more chances their will be for fraud and abuse. The system is terrible now, and if the current bill passes in it's current state it will be worse. It will cost the patient, the state, and dispensaries more.