Back around 2000-2002, I too had dial-up internet and had set up an auto-dialer to make sure the connection stayed up, as it was being shared throughout the hou

Back around 2000-2002, I too had dial-up internet and had set up an auto-dialer to make sure the connection stayed up, as it was being shared throughout the house via ethernet and wifi. My memory is that we started getting very large bills. When we asked about them, we were told that it was because we had several concurrent connections. What was happening is that my script to detect the connection being down was finding that and reconnecting before their system could mark the disconnection. Then my computer would reconnect and they'd never see the original disconnection, and so they'd think we had concurrent sessions and charged us accordingly. I remember them being surprised when they figured out that bug in their stuff. I think it helped that all of the connections came from the same phone number.