Let's say you place a decent-sized order and it sits on the market unaccepted for over 24 hours while the price of Bitcoin soars. The $200 worth of bitcoin I have put down is now worth $220.
So I cancel the order and re-place the same order with the same vendor, I now have the same order sitting with the same vendor but I now have an extra $20 in my account.
Is this tacky or cheap? If you were a vendor would you frown on this type of behavior and not accept the order?
Don't be surprised when vendors cancel your orders after the price falls.