So true, but better to play it safe now as Amz seems to be doing random checks and closing down accts. Some members have reported being checked by Amz and told them they were using Amz pay strictly for miles and got shut down.
Also my own family members were shut down after 6 mths for doing A-B-A back and forth sending. So yes they do check and with more people doing Amz now, (and some abusing the system) its just a matter of time before they get more restrictive.