They'll be denied, cause the port on the switch will stay in the unauthorized state and not pass traffic. The following link has some good info on it:
http://www.cisco.com/en/US/products/hw/switches/ps708/products_configuration_guide_chapter09186a00800da6ff.html#57739
Specifically:
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If a client that does not support 802.1X is connected to an unauthorized 802.1X port, the switch requests the client's identity. In this situation, the client does not respond to the request, the port remains in the unauthorized state, and the client is not granted access to the network.
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