Being a pit trader is the same as being given a license to steal, plain and simple. I'm sure there are some honest traders out there, but being in a position where you make a trade, then can wait a minute or two to see where prices went before deciding if the trade will be your own trade or a trade for your client is just too big a temptation for most people.
I place a limit order to buy at 101 11/32. My broker makes this trade, then the price 5 seconds later shoots to 101 14/32. He sells at 101 14/32 and I get back a "no fill". He pockets the 3/32. However, if the price immediately drops to 101 8/32 then I get back my fill at 101 11/32 and I get to keep the loss. It's a guaranteed trade for the broker. We should all be so lucky....
I place a limit order to buy at 101 11/32. My broker makes this trade, then the price 5 seconds later shoots to 101 14/32. He sells at 101 14/32 and I get back a "no fill". He pockets the 3/32. However, if the price immediately drops to 101 8/32 then I get back my fill at 101 11/32 and I get to keep the loss. It's a guaranteed trade for the broker. We should all be so lucky....