The virtual participation system is great. However, sometimes I want to simulate a contest more realistically, and simply testing system tests becomes a problem as some problem setters tend to have weak pretests.

So here is my solution: virtual participation will only test pretests by default, but you can still turn on system test mode. And when the participation ends, a "Run System Test" button will appear and you can run systests for your own submission, just like how TopCoder works.