[longtime reader, longtime lurker] I'm in the health evidence business, and your question made me curious, so I went and did a (very) quick check of http://www.thecochranelibrary.com, googlescholar and PubMed and there are, as far as I can see, no trials or systematic reviews to provide evidence for or against AAC (which really does seem like a lame policy). It sounds like a great opportunity for some enterprising soul to get some research funding and do a study on it. Or the service could just do the sensible thing and chuck it out.