In general, the client socket needs to timeout on black-holed connection attempts (several minutes), and the server never sees a TCP handshake packet if the IP is on the global routers ban lists.

As a side note, some people build spider traps that reply with a pre-baked bzip file as a spoofed HTML compressed response. Thus a client program dutifully decompresses a few TB sized document, and browser exits due to memory issues. Note most modern Browsers are wise to this trick these days, but I doubt a dodgy plugin disk-usage limit check would catch a client side storage-flood. People shouldn't do this though, even if it is epically funny and harmless. =)