There seems to be the idea that by changing the rule to "you cannot share CPU's or GPU's in 3D" is somehow complex ???
How is it any more complex than the current rule "you cannot share GPU's in 3D" ???
Proving that someone is sharing GPU's is next to impossible, yet it is still the rule.
In either the current rule situation or by changing the rule to "no sharing of CPU's or GPU's for 3D" you are relying upon the conscience or eithics of the person submitting the bench.