I sent out about 50 requests for shoes. I was informed that 12 did not get the request because I had already asked them for shoes. I haven't sent requests for anything in ages. Is this because some players have more than one account?

Adding: I just tried a few more. I think this happens when I was selecting my neighbors, somehow they became unchecked and I rechecked them and sent . and was counted as being sent. Anyways, that's my speculation.