Good point henry -- typically the big hit comes a year or two down the line, not straight away. It's not even necessarily a string of losers, it could partly be handing back a large part of open equity.
One of the things I look at on a simulation is exposure -- this is the average amount of open equity in the market. So for example, if you trail stop with a 10 day high/low, the exposure might be 15 pct, whereas with a 20 day high/low, it might be 25 pct. Now, the second method will give you (perhaps) a better raw CAGR, but it comes at the expense of more volatile equity curve, and greater need for substantial margin.