Omega finally releases Phelps photo sequence

So apparently you can be touch the wall before your opponent but to finish you have to apply the appropriate amount of pressure to the touch pad.

Chianese explained that it requires 3 kilograms (6.6 pounds) of pressure to activate the touchpad.

"Any less and waves would set it off," Chianese said. "You can’t just put your fingertips on the pad, you really have to push it. We explained all this directly after the race to (Cavic) and his coach."

via d.yimg.com