Page 128 of the v4 Reference Guide shows a picture of preferred parking signage that includes the words "Permit Required". Are we to infer that all green vehicles must now be deemed and permitted as 'green' per the referenced standard by the project owners or by some other means? Also, p. 121 uses the phrase (under Requirements), "Clearly identify and enforce for sole use by green vehicles." Does that mean that personnel need to be patrolling the parking lot? I don't see any qualification anywhere of this term 'enforce'... Additional guidance would be greatly appreciated, as we don't know what to tell our clients. Thank you in advance.