ok, ipfw is used to manipulate the stateful firewall, found that. so when I executed the ipfw command to delete two rules concerning a test mac, the firewall did indeed deny outbound and inbound access to the machine without logging into the captive portal.
Now, one would think that the passthrough mac address page would, when refreshed, show that this mac has been deleted, but no. so obviously the information is being cached somewhere. Even though it showed as a pass through mac, ipfw had successfully (of course) deleted the rule. When I edited the mac entry, and saved it, it went back into the ruleset for ipfw.
Question remains: where is this information cached? is it encrypted? Standing by…... :)