My office email server drops any attachment that fails a multitude of tests. We also strip email of any HTML back to pure ascii.
If AOL is the recipient or along the path, then you get to call them to sort it out.
Bob
1. Attachments sent have disappeared by recipient's inbox. (several cases) Relaying through a third party to same recipient: attachment is received.
2. Several recipients will not receive my e-mails. I get error message. When I "reply" to their messages, they kick back. Yet others send to them with no difficulty.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic