experience. 1) look at the quantity (if it is different than all the other options then it may be a customer order) 2) look at the spread of the option at the CBOE (if unusally tight then one side is probably a client order) Not that it matters really who is on the bid/ask but the bottom line is that 95-99% of equity options (whether its a customer order or the DPM's market) on the CBOE should provide auto executions as long as the market isn't locked or crossed.
I just cancelled a cboe order on the bid and it wasn't held. Was just as quick as PSE and ISE. I will send them a few orders today to test them.
yes, the CBOE is quick to cancel as long as your market is posted. However, it can take several minutes for them to post your bid/ask if you are improving the market so be careful