More importantly, a quick study in logic shows there should be no requirement for the existing space to meet RFC2050 requirements -- the space is already allocated. After the renumbering period there's no net damage to the IPv4 "shortage" since similar amounts of space would be assigned, but it would be a great help to the global routing system.
The problem is that PA space is questionable. As you stated, if the only way to do something one wants to do is to lie/cheat/steal/kill, many people will do it. Some of the "P" in the PA will break the rules in order to drive sales. So, the inherent assumption that a provider is already compliant is not a given, which strikes down the argument. I'ld advocate for mandatory compliance checking on each allocation request or biannually, whichever is more frequent. Of course, I'ld also advocate that it a provider is below 25% usage, that they have address space rescinded, including blocks not presently assigned to any RIR. If an entity can not be contacted for 2 compliance periods (for example, a swamp /24 to some long-dead company) that they be considered defunct, and the space rescinded. But, then again, I'm fairly liberal. I'm sure the more conservative among us (and those hanging onto former customer /24s, /8s, etc) would absolutely hate this, since they are getting something for nothing and don't like having to play by the same rules as the rest of us.