You can choose that Collective2 should refuse to fill your limit orders until at least one real-life AutoTrader of your strategy is filled in his or her brokerage account.
Which to choose?
There is no "better" or "worse" choice. The best choice depends on your strategy's trading style, and the instruments it trades and their market liquidity. Generally speaking, select "Wait for AutoTraders" if you trade instruments with less liquidity, or if you try to scalp limit orders.
By default, whenever your strategy issues a limit order, Collective2 will recognize that your limit is "filled" whenever we see the price is touched anywhere in the market.
From Strategy page -> Manage -> Edit Your Strategy, you will see the these 2 choices:
Note: If your strategy does not currently have any real-broker-account AutoTraders. Your choice will apply as soon as you acquire your first AutoTrader.