I used AMR a few days ago to make accounts (and confirm them), but only got around to writing and submitting an article tonight. I found a few accounts had been banned. I guess something gave away I was using AMR - I'm thinking perhaps the User Agent (maybe it could be updated to rotate UAs between Chrome, Firefox and Opera ones for Windows?) as it seems to be a slightly unusual (even if valid) one:
Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; InfoPath.2; Media Center PC 5.0; SLCC1; .NET4.0C; Tablet PC 2.0)
Or it could be something else in the http request, I guess.