The robot controller will not enforce autonomous by neutralizing the operator interface inputs before your user program sees them. You are free, however, to ignore data from the OI.
You could set up a switch on the OI which would initiate autonomous operations. (I haven't tried it, but it is conceivable that pin 5 of the competition port may actually be passed in the PB_mode byte, so that you might be able to use the same competition port dongle you already have.... You do have one, don't you?
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